European Journal of Operational Research

Introduction

Editorial policies

The European Journal of Operational Research (EJOR) publishes high quality, original papers that contribute to the methodology of operational research (OR) and to the practice of decision making. Extended versions of papers published in conference proceedings are not solicited. The relation with ongoing research should be demonstrated by providing proper reference to the recent OR literature. With application papers, originality should be demonstrated by applying OR to a problem with interesting new aspects or by providing fresh insights leading to successful implementation. Practitioners often suffer from the need to conceal commercial secrets. Referees will take this into sympathetic consideration when advising on an application paper, but it will not be allowed to detract from the clarity of the presentation.

Types of paper
EJOR includes the following types of papers:
• Theory and Methodology Papers
Papers presenting original research results contributing to the methodology of OR and to its theoretical foundations. The Theory and Methodology Papers will be classified by the Editors into one of seven sub-headings, based on the List of EJOR Keywords:
1. Continuous Optimization
2. Discrete Optimization
3. Production, Manufacturing, Transportation and Logistics
4. Stochastics and Statistics
5. Decision Support
6. Analytics, Computational Intelligence and Information Management
7. Interfaces with Other Disciplines
• Innovative Applications of OR
Papers describing novel ways to solve real problems. A paper presenting an Innovative Application of OR may be worthy of publication simply because it can be used to convince managers of the value to be gained by applying OR to particular problems.
• Short Communications
Short Communications are considered, but only if they correct important errors found in papers published in EJOR during the last 5 years.
• Invited Reviews
An Invited Review is expected to be a creative synthesis of the work recently done in an important field. Presentation of models and solution methods proposed up to now should be followed by definition of open problems, and indication of prospective research directions. It should also be strongly based on papers previously published in OR journals, including EJOR. A literature review cannot be just a list of papers with their short summaries and classification statistics, but should also contain an outline of adopted methodologies, their reference to practice, and a thorough analysis of their properties. Usually, the Invited Review papers are written by authors having a strong record of publications in the field and well known to EJOR as authors and reviewers. Note: Anyone interested in writing a review is requested to suggest a topic to one of the Editors, or to a member of the editorial board of EJOR before submitting a paper. If the topic is considered suitable, an invitation to submit will then be given by one of the editors. Unsolicited review papers will be returned to the authors.
• Special Issue Papers
EJOR occasionally publishes groups of papers on topical themes. Submissions are handled by one or more Guest Editors. Special issues that are open for new submissions will each have their own paper type available in the submission system.

Advice from the Editors
The European Journal of Operational Research strives to provide a thorough review process while ensuring timely feedback. Immediate decisions (e.g., desk reject or reviewer invitation) usually take less than a week. For papers sent out for review, it takes about 3 months on average to the first round decision and just under a year on average from submission to publication for accepted papers (including author revision time). Please realize that these durations vary due to, e.g., the process to find the right reviewers, the time that reviewers need to assess a paper, and the number of review rounds.

EJOR has a very high volume of submissions and acceptance is competitive. Therefore, papers that do not contain a major new research finding, or novel approach to the application of OR, are likely to be rejected. A paper may also be rejected because - in the opinion of the Editor - it does not make a sufficient scientific contribution.

All papers will be subject to an initial screening and technical check by the EJOR Managing Editor. Please carefully read the guidelines for NEW SUBMISSIONS below. If your article is written in poor English or does not contain all of the required components, it will not progress to peer review stage.

Articles that do not pass the Managing Editor screening or do not conform to the Editorial Policy are likely to be rejected without peer review.

• Are you making a new submission?
All papers will be screened by the EJOR Managing Editor to make sure they conform to all Journal requirements. Please carefully read the PREPARATION section of this Guide for Authors for more details on each of the required components for New Submissions. We recommend you check this even if you have submitted to EJOR recently, as some requirements may have changed.
• Has your submission been returned by the Managing Editor?
The Editorial Policy of EJOR is such that your paper will not be able to progress to peer review until it is of a good standard of English and contains all of the required components. If you have received the message “Send Back to Author” then your paper has not passed the technical checks and unfortunately does not comply with one or more of the Journal policies. Please carefully read the feedback from the Managing Editor to establish the reason your paper was returned, then consult the relevant PREPARATION section below for more information on how to improve and progress your paper.
• Have you received an Editorial decision of Revise?
If an Editor has made the decision that you need to revise your paper, for example “Minor Revision” or “Major Revision”, please carefully read the decision letter and any Editor and reviewer comments in order to make the required changes to your paper. When you are ready to resubmit, visit the REVISED SUBMISSIONS section. It contains advice, and details of the extra components required with your resubmission.
• The authors should refrain from submitting simultaneously more than one paper on a similar topic.

Before you begin

Ethics in publishing

Please see our information on Ethics in publishing.

Ethical statement

Papers going through the peer-review process, before being accepted for publication, obtain an average of over five reports from three reviewers. For each paper that enters the review process, several fellow scientists devote their time and efforts to reading this work and providing comments. To keep this process operational and ensure a fair distribution of the workload, we expect that all submitting authors and co-authors are willing to review papers. We understand there may be reasons you cannot accept a request at certain times, however, refusing many requests over a long period of time is unwanted and not fair on other reviewers. After all, if you have time to write papers, then there should be time to review other papers, despite other teaching, administrative or editorial duties.

As editors, we observe increased concerns of authors regarding the proper re-use of published material. In general, copying copyrighted material constitutes plagiarism unless there is an agreement of the copyright holder and the copied material is referenced appropriately (the identical material needs to be highlighted and the source reported with the page number from which the text is taken). EJOR prohibits plagiarism of any kind. Papers extending previously published results (e.g., as is common for conference proceedings) therefore need to ensure that previously copyrighted material is not re-published. In general, the journal does not consider extended versions of conference proceedings.

Finally, we expect that all authors of a submitted paper have read the complete paper and have played an important part in the research. Acting as or allowing a "ghost-author" (for financial remuneration) is unethical and may lead to a submission ban for all involved authors. We highly disapprove of such behavior and would like to raise awareness in the community about the fact that it is against ethical rules in publishing. Any suggested change in the set of authors after a first submission has to be carefully explained in the submission letter of a new version, and will typically not be accepted after a minor revision decision.

Declaration of interest

All authors must disclose any financial and personal relationships with other people or organizations that could inappropriately influence (bias) their work. Examples of potential competing interests include employment, consultancies, stock ownership, honoraria, paid expert testimony, patent applications/registrations, and grants or other funding. Authors must disclose any interests in two places: 1. A summary declaration of interest statement in the title page file (if double anonymized) or the manuscript file (if single anonymized). If there are no interests to declare then please state this: 'Declarations of interest: none'. 2. Detailed disclosures as part of a separate Declaration of Interest form, which forms part of the journal's official records. It is important for potential interests to be declared in both places and that the information matches. More information.

Declaration of generative AI in scientific writing

The below guidance only refers to the writing process, and not to the use of AI tools to analyse and draw insights from data as part of the research process.

Where authors use generative artificial intelligence (AI) and AI-assisted technologies in the writing process, authors should only use these technologies to improve readability and language. Applying the technology should be done with human oversight and control, and authors should carefully review and edit the result, as AI can generate authoritative-sounding output that can be incorrect, incomplete or biased. AI and AI-assisted technologies should not be listed as an author or co-author, or be cited as an author. Authorship implies responsibilities and tasks that can only be attributed to and performed by humans, as outlined in Elsevier’s AI policy for authors.

Authors should disclose in their manuscript the use of AI and AI-assisted technologies in the writing process by following the instructions below. A statement will appear in the published work. Please note that authors are ultimately responsible and accountable for the contents of the work.

Disclosure instructions
Authors must disclose the use of generative AI and AI-assisted technologies in the writing process by adding a statement at the end of their manuscript in the core manuscript file, before the References list. The statement should be placed in a new section entitled ‘Declaration of Generative AI and AI-assisted technologies in the writing process’.

Statement: During the preparation of this work the author(s) used [NAME TOOL / SERVICE] in order to [REASON]. After using this tool/service, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the publication.

This declaration does not apply to the use of basic tools for checking grammar, spelling, references etc. If there is nothing to disclose, there is no need to add a statement.

Submission declaration and verification

Submission of an article implies that the work described has not been published previously (except in the form of an abstract, a published lecture or academic thesis, see 'Multiple, redundant or concurrent publication' for more information), that it is not under consideration for publication elsewhere, that its publication is approved by all authors and tacitly or explicitly by the responsible authorities where the work was carried out, and that, if accepted, it will not be published elsewhere in the same form, in English or in any other language, including electronically without the written consent of the copyright-holder. To verify compliance, your article may be checked by Crossref Similarity Check and other originality or duplicate checking software.

Use of inclusive language

Inclusive language acknowledges diversity, conveys respect to all people, is sensitive to differences, and promotes equal opportunities. Content should make no assumptions about the beliefs or commitments of any reader; contain nothing which might imply that one individual is superior to another on the grounds of age, gender, race, ethnicity, culture, sexual orientation, disability or health condition; and use inclusive language throughout. Authors should ensure that writing is free from bias, stereotypes, slang, reference to dominant culture and/or cultural assumptions. We advise to seek gender neutrality by using plural nouns ("clinicians, patients/clients") as default/wherever possible to avoid using "he, she," or "he/she." We recommend avoiding the use of descriptors that refer to personal attributes such as age, gender, race, ethnicity, culture, sexual orientation, disability or health condition unless they are relevant and valid. When coding terminology is used, we recommend to avoid offensive or exclusionary terms such as "master", "slave", "blacklist" and "whitelist". We suggest using alternatives that are more appropriate and (self-) explanatory such as "primary", "secondary", "blocklist" and "allowlist". These guidelines are meant as a point of reference to help identify appropriate language but are by no means exhaustive or definitive.

Reporting sex- and gender-based analyses

Reporting guidance
For research involving or pertaining to humans, animals or eukaryotic cells, investigators should integrate sex and gender-based analyses (SGBA) into their research design according to funder/sponsor requirements and best practices within a field. Authors should address the sex and/or gender dimensions of their research in their article. In cases where they cannot, they should discuss this as a limitation to their research's generalizability. Importantly, authors should explicitly state what definitions of sex and/or gender they are applying to enhance the precision, rigor and reproducibility of their research and to avoid ambiguity or conflation of terms and the constructs to which they refer (see Definitions section below). Authors can refer to the Sex and Gender Equity in Research (SAGER) guidelines and the SAGER guidelines checklist. These offer systematic approaches to the use and editorial review of sex and gender information in study design, data analysis, outcome reporting and research interpretation - however, please note there is no single, universally agreed-upon set of guidelines for defining sex and gender.

Definitions
Sex generally refers to a set of biological attributes that are associated with physical and physiological features (e.g., chromosomal genotype, hormonal levels, internal and external anatomy). A binary sex categorization (male/female) is usually designated at birth (""sex assigned at birth""), most often based solely on the visible external anatomy of a newborn. Gender generally refers to socially constructed roles, behaviors, and identities of women, men and gender-diverse people that occur in a historical and cultural context and may vary across societies and over time. Gender influences how people view themselves and each other, how they behave and interact and how power is distributed in society. Sex and gender are often incorrectly portrayed as binary (female/male or woman/man) and unchanging whereas these constructs actually exist along a spectrum and include additional sex categorizations and gender identities such as people who are intersex/have differences of sex development (DSD) or identify as non-binary. Moreover, the terms ""sex"" and ""gender"" can be ambiguous—thus it is important for authors to define the manner in which they are used. In addition to this definition guidance and the SAGER guidelines, the resources on this page offer further insight around sex and gender in research studies.

Author contributions

For transparency, we require corresponding authors to provide co-author contributions to the manuscript using the relevant CRediT roles. The CRediT taxonomy includes 14 different roles describing each contributor’s specific contribution to the scholarly output. The roles are: Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Roles/Writing - original draft; and Writing - review & editing. Note that not all roles may apply to every manuscript, and authors may have contributed through multiple roles. More details and an example.

Authorship

An author of a paper submitted to EJOR is considered to be an individual who has made a significant intellectual contribution to the study. Four criteria must all be met to be credited as an author:
•Substantial contribution to the study at the stage of conception and design, problem modelling, data acquisition, solution method, analysis and interpretation of results.
•Drafting or revising the article for intellectual content.
•Approval of the final version.
•Agreement to be accountable for all aspects of the work related to the accuracy or integrity of any part of the work.

Individuals who are involved in a study but don't satisfy the above criteria for authorship, should be listed as 'Contributors' or 'Acknowledged Individuals'. Examples include: assisting the research by providing advice, sharing the data, providing research space, departmental oversight, and obtaining financial support.

There should be at most 10 authors. In the case the list of authors should include from 7 to 10 individuals, the leading author should present to the Editor a convincing argumentation specifying the role of each listed author prior to the submission. In this case, the submission of a paper can only be made upon an agreement of the Editor. Authors are expected to consider carefully the list and order of authors before submitting their manuscript and provide the definitive list of authors at the time of the original submission. Any addition, deletion or rearrangement of author names in the authorship list should be made only before the manuscript has been accepted and only if approved by the journal Editor. To request such a change, the Editor must receive the following from the corresponding author: (a) the reason for the change in author list and (b) written confirmation (e-mail, letter) from all authors that they agree with the addition, removal or rearrangement. In the case of addition or removal of authors, this includes confirmation from the author being added or removed.
Only in exceptional circumstances will the Editor consider the addition, deletion or rearrangement of authors after the manuscript has been accepted. While the Editor considers the request, publication of the manuscript will be suspended. If the manuscript has already been published in an online issue, any requests approved by the Editor will result in a corrigendum.

Article transfer service
This journal uses the Elsevier Article Transfer Service to find the best home for your manuscript. This means that if an editor feels your manuscript is more suitable for an alternative journal, you might be asked to consider transferring the manuscript to such a journal. The recommendation might be provided by a Journal Editor, a dedicated Scientific Managing Editor, a tool assisted recommendation, or a combination. If you agree, your manuscript will be transferred, though you will have the opportunity to make changes to the manuscript before the submission is complete. Please note that your manuscript will be independently reviewed by the new journal. More information.

Copyright

Upon acceptance of an article, authors will be asked to complete a 'Journal Publishing Agreement' (see more information on this). An e-mail will be sent to the corresponding author confirming receipt of the manuscript together with a 'Journal Publishing Agreement' form or a link to the online version of this agreement.

Subscribers may reproduce tables of contents or prepare lists of articles including abstracts for internal circulation within their institutions. Permission of the Publisher is required for resale or distribution outside the institution and for all other derivative works, including compilations and translations. If excerpts from other copyrighted works are included, the author(s) must obtain written permission from the copyright owners and credit the source(s) in the article. Elsevier has preprinted forms for use by authors in these cases.

For gold open access articles: Upon acceptance of an article, authors will be asked to complete a 'License Agreement' (more information). Permitted third party reuse of gold open access articles is determined by the author's choice of user license.

Author rights
As an author you (or your employer or institution) have certain rights to reuse your work. More information.

Elsevier supports responsible sharing
Find out how you can share your research published in Elsevier journals.

Role of the funding source

You are requested to identify who provided financial support for the conduct of the research and/or preparation of the article and to briefly describe the role of the sponsor(s), if any, in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication. If the funding source(s) had no such involvement, it is recommended to state this.

Open access

Please visit our Open Access page for more information about open access publishing in this journal.

Submission

Our online submission system guides you stepwise through the process of entering your article details and uploading your files. The system converts your article files to a single PDF file used in the peer-review process. Editable files (e.g., Word, LaTeX) are required to typeset your article for final publication. All correspondence, including notification of the Editor's decision and requests for revision, is sent by e-mail.

Submit your article

Please submit your article via our Editorial Site.

Peer review

The continuing success of EJOR relies not only on high quality submissions, but also on high quality reviews. The editors therefore ask all authors to act also as reviewers and to register for an account in EM if they are not already registered.

This journal operates a single blind review process. All contributions will be screened by the EJOR Managing Editor for language and completeness and, if they pass, assessed by an EJOR Editor for suitability for the journal. Papers deemed suitable are typically sent to a minimum of two independent expert reviewers to assess the scientific quality of the paper. The Editor is responsible for the final decision regarding acceptance or rejection of articles. The Editor's decision is final. More information on types of peer review

Preparation

Queries

For questions about the editorial process (including the status of manuscripts under review) or for technical support on submissions, please visit our Support Center.

NEW SUBMISSIONS

New submissions should be submitted as a single file, which will be used in the refereeing process. The single manuscript file can be a PDF file or word document. If you prefer to do so, you may still provide some or all source files in addition to the single file. Please note that individual figure files larger than 10MB must be uploaded separately. The total size of the combined submitted files must not exceed 30MB.

If your source files are in LaTeX, please visit our LaTeX site.

Requirements for New Submissions

Your article will be screened by the EJOR Managing Editor and must conform to the following guidelines in order to progress:

1. Standard of English
Please write your text in good English (American or British usage is accepted, but not a mixture of these). Authors who feel their English language manuscript may require editing to eliminate possible grammatical or spelling errors and to conform to correct scientific English may wish to use the English Language Editing service available from Elsevier's WebShop.
Papers written in poor English will immediately be returned to the authors.

2. Article format
• Page extent
The article should not exceed 30 pages (or 10 pages for Short Communications). The page limit includes the abstract, figures and tables, main manuscript, and references. All necessary but non-essential additional material can be uploaded as Supplementary Materials. For instance, long descriptions of empirical settings (summarised in the main text), complete data and detailed results that are fundamental for result replication (summarised in the main text), and very technical or repetitive proofs can go to the Supplementary Materials. However, case/data descriptions and other proofs are typically essential material and should thus be included (as appendices) in the main manuscript. Not adhering to these rules may result in a desk rejection.
• Format of text
The article should be A4 or letter size, in single column pages, with 11pt font and 1.5 line spacing.
Please do not use double column format or line numbering; line numbers will be added to your paper by the submission system.
• Figures and tables
Please ensure that figures and tables embedded in the single manuscript file are placed next to the relevant text in the article, not at the bottom or top of the file.
Figures should be of a high enough quality for refereeing.
• Reference format
References should follow the style used by the American Psychological Association (APA), with the reference list arranged alphabetically. The use of DOIs is encouraged. Please see the references section in MORE INFORMATION for details.

3. Article structure
The structure should be easy to follow. Sections should be clearly defined and numbered, with headings on separate lines.
Please include the following sections, taking into account the requirements for each:
• Title page
Article title. Please avoid formulae wherever possible. Abbreviations and acronyms are not permitted.
All author names and affiliations, including email addresses and postal addresses.
Clearly indicate which author is the corresponding author.
• Abstract
A 50-250 word summary of the article.
Please do not include formulae.
Please do not include unqualified abbreviations or acronyms. Any abbreviation or acronym that you have defined in the abstract should be redefined in the manuscript text.
References should be avoided, but if necessary, include the full reference.
• Keywords
The first keyword should be selected from the list of EJOR Keywords.
Please note that the first keyword should also be entered separately under ?Section/Category? in the submission system.
Please include up to 4 additional keywords of your choice.

4. Supplementary materials
If your article contains any videos or other supplementary materials, these should be included in your initial submission for peer review purposes.
Please upload supplementary materials as separate files. Note that they will be available in the online version only.

New Submissions: file inventory

Mandatory
• Manuscript file in PDF or Word format

Optional
• Cover letter
• Manuscript source files
• Graphical abstract*
• Highlights*
• Supplementary materials*

Please note that for new submissions of previoulsy rejected papers, an additional "Comments to reviewers" file must also be included.

New Submissions: checklist

Before submitting a new manuscript to EJOR, please ensure that your article:
• Conforms to Elsevier's Ethical Guidelines for Journal Publication
• Is written in good British or American English
• Does not exceed 30 manuscript pages (or 10 pages if a Short Communication)
• Uses single column formatting, 11pt font, 1.5 line spacing, and has no line numbers
• Has figures and tables embedded next to relevant text
• Includes references in APA format, with an alphabetical reference list*
• Includes a Title Page, containing all of the essential title page information*
• Includes one keyword from the list of EJOR Keywords and no more than 4 additional keywords*
• Does not contain formulae, abbreviations or acronyms in the Title
• Does not contain formulae or unqualified abbreviations or acronyms in the Abstract
• Does not contain unqualified abbreviations or acronyms in the main text
• Is in a single PDF or Word document (source files and/or supplementary materials* can be uploaded separately if needed)

*Please see the relevant sections in MORE INFORMATION for details.

REVISED SUBMISSIONS

After peer review, if an editorial decision of "Revise" is made, authors are asked to update their manuscript, according to the advice given by the Editors and referees. Authors are advised to revise and resubmit their manuscript no later than 6 months after the decision. If the revision is not submitted within this time, the review process of the paper will be terminated, and the revised paper will need to be submitted as a new submission.

Requirements for Revised Submissions

All revised submissions will be screened (again) by the EJOR Managing Editor, before being passed back to the relevant Editor.
In order for the Editor and/or referees to be certain that the requested changes have been carried out, please clearly outline all of the changes made to the article since its last submission, for example by colouring any new text in red. Changes should also be referred to in the 'Comments to reviewers' file. If there are too many changes, please explain this in the 'Comments to reviewers' file. Note that there is no need to include an additional, ‘clean’, version of the manuscript.

At revision stage, several additional components are needed. These should be submitted as separate files:
• Highlights
A short collection of bullet points that convey the core findings of the article.
Please see the Highlights section in MORE INFORMATION for details.
• Comments to reviewers
A separate document containing author responses to each of the Editor and/or reviewer queries and suggestions. Each of the changes made to the manuscript since the last review should be explained in this file.
• Manuscript source files
Regardless of the file format of the original submission, at revision stage authors must provide editable files of the entire manuscript.
These source files (e.g. Word, LaTeX) are required to typeset your article for final publication, in the event that an editorial decision of "Accept" is later made.

Revised submissions: file inventory

Mandatory
• Manuscript file, with changes clearly shown
• Highlights*
• Comments to reviewers
• Manuscript source files

Optional
• Cover letter
• Graphical abstract*
• Supplementary materials*

Revised submissions: checklist

Before submitting a revised manuscript to EJOR, please ensure that your article (still):
• Conforms to Elsevier's Ethical Guidelines for Journal Publication
• Is written in good British or American English
• Does not exceed 30 manuscript pages (or 10 pages if a Short Communication)
• Uses single column formatting, 11pt font, 1.5 line spacing, and has no line numbers
• Has figures and tables embedded next to relevant text
• Includes references in APA format, with an alphabetical reference list*
• Includes a Title Page, containing all of the essential title page information*
• Includes one keyword from the list of EJOR Keywords and no more than 4 additional keywords*
• Does not contain formulae, abbreviations or acronyms in the Title
• Does not contain formulae or unqualified abbreviations or acronyms in the Abstract
• Does not contain unqualified abbreviations or acronyms in the main text
• Shows changes made to the manuscript
• Includes a separate Highlights* file
• Includes a separate Comments to reviewers file
• Includes separate source files

*Please see the relevant sections in MORE INFORMATION for details.

Essential title page information

• Title. Concise and informative. Titles are often used in information-retrieval systems. Abbreviations, formulae and acronyms are not permitted.
• Author names and affiliations. Please clearly indicate the given name(s) and family name(s) of each author and check that all names are accurately spelled. Present the authors' affiliation addresses (where the actual work was done) below the names. Indicate all affiliations with a lower-case superscript letter immediately after the author's name and in front of the appropriate address. Provide the full postal address of each affiliation, including the country name and, if available, the e-mail address of each author.
• Corresponding author. Clearly indicate who will handle correspondence at all stages of refereeing and publication, also post-publication. Ensure that the e-mail address is given and that contact details are kept up to date by the corresponding author.
• Present/permanent address. If an author has moved since the work described in the article was done, or was visiting at the time, a 'Present address' (or 'Permanent address') may be indicated as a footnote to that author's name. The address at which the author actually did the work must be retained as the main, affiliation address. Superscript Arabic numerals are used for such footnotes.

Abstract

A concise and factual abstract of between 50 and 250 words is required for all New and Revised Submissions. The abstract should state briefly the purpose of the research, the principal results and major conclusions. An abstract is often presented separately from the article, so it must be able to stand alone. For this reason, references should be avoided, but if essential, the full reference must be included. (For Short Communications, which address deficiencies in previous EJOR papers, the full reference to the original paper should always be included.)
Abstracts should not contain any formulae, or any unqualified abbreviations or acronyms. Abbreviations and acronyms used and defined within the abstract should be defined for a second time within the manuscript main text.

Graphical abstract
Although a graphical abstract is optional, its use is encouraged as it draws more attention to the online article. The graphical abstract should summarize the contents of the article in a concise, pictorial form designed to capture the attention of a wide readership. Graphical abstracts should be submitted as a separate file in the online submission system. Image size: Please provide an image with a minimum of 531 × 1328 pixels (h × w) or proportionally more. The image should be readable at a size of 5 × 13 cm using a regular screen resolution of 96 dpi. Preferred file types: TIFF, EPS, PDF or MS Office files. You can view Example Graphical Abstracts on our information site.

Highlights
Highlights are optional for New Submissions but mandatory for Revised Submissions, as they are included within all accepted papers in this Journal. They consist of a short collection of bullet points that convey the core findings of the article and should be submitted in a separate editable file in the online submission system. Please use 'Highlights' in the file name and include 3 to 5 bullet points (maximum 85 characters, including spaces, per bullet point). You can view example Highlights on our information site.
Highlights must not contain acronyms, abbreviations, formulae, or references.

Keywords

Keywords are required for all New Submissions and Revised Submissions. Selected keywords should be put in the same order in 2 keyword sections (i.e., during submission process as well in manuscript after abstract). At least the first keyword should be selected from the official list of EJOR Keywords, below. Please note that the first keyword should also be entered separately under 'Section/Category' in the submission system. Some keywords from outside the list may be added but the total number of keywords should not exceed five.

The letters before the keywords represent the Editor who will receive the paper, if it progresses through the inital screening process.

Codes of Editors: (R) - Steffen Rebennack; (B) - Emanuele Borgonovo; (Y) - Michael Yearworth; (O) - José Fernando Oliveira; (S) - Roman Slowinski; (T) - Ruud Teunter

List of EJOR keywords
• (S) Analytics
• (R) Applied probability
• (S) Artificial intelligence
• (S) Assignment
• (R) Auctions/bidding
• (Y) Behavioural OR
• (R) Bioinformatics
• (S) Branch and bound
• (O) Combinatorial optimization
• (Y) Community operational research
• (S) Complexity theory
• (R) Computing science
• (R) Conic programming and interior point methods
• (Y) Control
• (Y) Cost benefit analysis
• (O) Cutting
• (Y) Data envelopment analysis
• (R) Data science
• (B) Decision analysis
• (Y) Decision processes
• (S) Decision support systems
• (B) Distributed decision making
• (O) Distribution
• (S) Dynamic programming
• (Y) E-commerce
• (O) OR in Education
• (Y) Ethics in OR
• (S) Evolutionary computations
• (R) Facilities planning and design
• (B) Finance
• (O) Flexible manufacturing systems
• (T) Forecasting
• (R) Fractional programming
• (S) Fuzzy sets
• (B) Game theory
• (O) Genetic algorithms
• (R) Global optimization
• (S) Goal programming
• (R) Graph theory
• (S) Group decisions and negotiations
• (O) Heuristics
• (Y) Human resource planning
• (O) Humanitarian logistics
• (R) Integer programming
• (T) Inventory
• (B) Investment analysis
• (S) Knowledge-based systems
• (R) Large scale optimization
• (R) Linear programming
• (O) Location
• (T) Logistics
• (R) Machine learning
• (T) Maintenance
• (T) Manufacturing
• (R) Markov processes
• (O) Metaheuristics
• (Y) Multi-agent systems
• (S) Multiple criteria analysis
• (S) Multiple objective programming
• (R) Multivariate statistics
• (R) Networks
• (R) Nonlinear programming
• (Y) OR in agriculture
• (R) OR in airlines
• (B) OR in banking
• (Y) OR in defence
• (Y) OR in developing countries
• (O) OR in disaster relief
• (R) OR in energy
• (B) OR in entertainment
• (R) OR in environment and climate change
• (Y) OR in government
• (O) OR in health services
• (O) OR in maritime industry
• (Y) OR in marketing
• (S) OR in medicine
• (R) OR in natural resources
• (B) OR in organization theory
• (Y) OR in research and development
• (O) OR in service industries
• (Y) OR in societal problem analysis
• (Y) OR in sports
• (R) OR in telecommunications
• (O) Packing
• (S) Portfolio optimization
• (S) Preference learning
• (R) Pricing
• (Y) Problem structuring
• (R) Production
• (Y) Productivity and competitiveness
• (B) Project management
• (S) Project scheduling
• (Y) Purchasing
• (R) Quality control
• (Y) Quality management
• (R) Queueing
• (B) Reliability
• (R) Replacement
• (O) Retailing
• (Y) Revenue management

• (B) Risk analysis
• (Y) Risk management
• (R) Robust Optimization
• (B) Sensitivity Analysis
• (S) Rough sets
• (O) Routing
• (B) Scenarios
• (S) Scheduling
• (R) Semi-infinite programming
• (B) Simulation
• (R) Stochastic processes
• (R) Stochastic programming
• (Y) Strategic planning
• (T) Supply chain management
• (Y) System dynamics
• (O) Timetabling
• (R) Traffic
• (O) Transportation
• (O) Travelling salesman
• (R) Uncertainty modelling
• (O) Validation of OR Computations

Formatting of funding sources
List funding sources in this standard way to facilitate compliance to funder's requirements:

Funding: This work was supported by the National Institutes of Health [grant numbers xxxx, yyyy]; the Bill & Melinda Gates Foundation, Seattle, WA [grant number zzzz]; and the United States Institutes of Peace [grant number aaaa].

It is not necessary to include detailed descriptions on the program or type of grants and awards. When funding is from a block grant or other resources available to a university, college, or other research institution, submit the name of the institute or organization that provided the funding.

If no funding has been provided for the research, it is recommended to include the following sentence:

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Footnotes
Footnotes should be used sparingly. Number them consecutively throughout the article. Many word processors build footnotes into the text, and this feature may be used. Should this not be the case, indicate the position of footnotes in the text and present the footnotes themselves separately at the end of the article.

Artwork

Electronic artwork
General points
• Make sure you use uniform lettering and sizing of your original artwork.
• Preferred fonts: Arial (or Helvetica), Times New Roman (or Times), Symbol, Courier.
• Number the illustrations according to their sequence in the text.
• Use a logical naming convention for your artwork files.
• Indicate per figure if it is a single, 1.5 or 2-column fitting image.
• For Word submissions only, you may still provide figures and their captions, and tables within a single file at the revision stage.
• Please note that individual figure files larger than 10 MB must be provided in separate source files.

A detailed guide on electronic artwork is available.
You are urged to visit this site; some excerpts from the detailed information are given here.
Formats
Regardless of the application used, when your electronic artwork is finalized, please 'save as' or convert the images to one of the following formats (note the resolution requirements for line drawings, halftones, and line/halftone combinations given below):
EPS (or PDF): Vector drawings. Embed the font or save the text as 'graphics'.
TIFF (or JPG): Color or grayscale photographs (halftones): always use a minimum of 300 dpi.
TIFF (or JPG): Bitmapped line drawings: use a minimum of 1000 dpi.
TIFF (or JPG): Combinations bitmapped line/half-tone (color or grayscale): a minimum of 500 dpi is required.
Please do not:
• Supply files that are optimized for screen use (e.g., GIF, BMP, PICT, WPG); the resolution is too low.
• Supply files that are too low in resolution.
• Submit graphics that are disproportionately large for the content.

Figure captions
Ensure that each illustration has a caption. A caption should comprise a brief title (not on the figure itself) and a description of the illustration. Keep text in the illustrations themselves to a minimum but explain all symbols and abbreviations used.

Tables

Please submit tables as editable text and not as images. Tables can be placed either next to the relevant text in the article, or on separate page(s) at the end. Number tables consecutively in accordance with their appearance in the text and place any table notes below the table body. Be sparing in the use of tables and ensure that the data presented in them do not duplicate results described elsewhere in the article. Please avoid using vertical rules and shading in table cells.

References

As the publishing language of the European Journal of Operational Research is English, authors are required to keep references to sources in other languages to a necessary minimum, and to provide an English translation of the title in parentheses.

Citation in text
Please ensure that all references cited in the text are present in the reference list (and vice versa). There should be no references cited in the Abstract, instead they should be replaced with text along the lines of 'as discussed in the recent literature' and then the reference should be cited in the Introduction. The one exception is Short Communication papers, where references can be included in the abstract but they must be written in full so ' Parker, D., Riley, K., Robinson, S., Symington, H., Tewson, J., Jansson, K., Ramkumar, S., Peck, D., 2015. Remanufacturing market study.' not ' (Parker et al., 2015).

Unpublished results and personal communications are not recommended in the reference list, but may be mentioned in the text. If these references are included in the reference list they should follow the standard reference style of the journal and should include a substitution of the publication date with either 'Unpublished results' or 'Personal communication'. Citation of a reference as 'in press' implies that the item has been accepted for publication.

Web references
As a minimum, the full URL should be given and the date when the reference was last accessed. Any further information, if known (DOI, author names, dates, reference to a source publication, etc.), should also be given. Web references can be listed separately (e.g., after the reference list) under a different heading if desired, or can be included in the reference list.

Data references
This journal encourages you to cite underlying or relevant datasets in your manuscript by citing them in your text and including a data reference in your Reference List. Data references should include the following elements: author name(s), dataset title, data repository, version (where available), year, and global persistent identifier. Add [dataset] immediately before the reference so we can properly identify it as a data reference. The [dataset] identifier will not appear in your published article.

Preprint references
Where a preprint has subsequently become available as a peer-reviewed publication, the formal publication should be used as the reference. If there are preprints that are central to your work or that cover crucial developments in the topic, but are not yet formally published, these may be referenced. Preprints should be clearly marked as such, for example by including the word preprint, or the name of the preprint server, as part of the reference. The preprint DOI should also be provided.

References in a special issue
Please ensure that the words 'this issue' are added to any references in the list (and any citations in the text) to other articles in the same Special Issue.

Reference management software
Most Elsevier journals have their reference template available in many of the most popular reference management software products. These include all products that support Citation Style Language styles, such as Mendeley. Using citation plug-ins from these products, authors only need to select the appropriate journal template when preparing their article, after which citations and bibliographies will be automatically formatted in the journal's style. If no template is yet available for this journal, please follow the format of the sample references and citations as shown in this Guide. If you use reference management software, please ensure that you remove all field codes before submitting the electronic manuscript. More information on how to remove field codes from different reference management software.

Reference style
Text: Citations in the text should follow the referencing style used by the American Psychological Association. You are referred to the Publication Manual of the American Psychological Association, Seventh Edition, ISBN 978-1-4338-3215-4, copies of which may be ordered online.
List: references should be arranged first alphabetically and then further sorted chronologically if necessary. More than one reference from the same author(s) in the same year must be identified by the letters 'a', 'b', 'c', etc., placed after the year of publication.
Examples:
Reference to a journal publication:
Van der Geer, J., Hanraads, J. A. J., & Lupton, R. A. (2010). The art of writing a scientific article. Journal of Scientific Communications, 163, 51–59. https://doi.org/10.1016/j.sc.2010.00372.
Reference to a journal publication with an article number:
Van der Geer, J., Hanraads, J. A. J., & Lupton, R. A. (2018). The art of writing a scientific article. Heliyon, 19, Article e00205. https://doi.org/10.1016/j.heliyon.2018.e00205.
Reference to a book:
Strunk, W., Jr., & White, E. B. (2000). The elements of style (4th ed.). Longman (Chapter 4).
Reference to a chapter in an edited book:
Mettam, G. R., & Adams, L. B. (2009). How to prepare an electronic version of your article. In B. S. Jones, & R. Z. Smith (Eds.), Introduction to the electronic age (pp. 281–304). E-Publishing Inc.
Reference to a website:
Powertech Systems. (2015). Lithium-ion vs lead-acid cost analysis. Retrieved from http://www.powertechsystems.eu/home/tech-corner/lithium-ion-vs-lead-acid-cost-analysis/. Accessed January 6, 2016
Reference to a dataset:
[dataset] Oguro, M., Imahiro, S., Saito, S., & Nakashizuka, T. (2015). Mortality data for Japanese oak wilt disease and surrounding forest compositions. Mendeley Data, v1. https://doi.org/10.17632/xwj98nb39r.1.
Reference to a conference paper or poster presentation:
Engle, E.K., Cash, T.F., & Jarry, J.L. (2009, November). The Body Image Behaviours Inventory-3: Development and validation of the Body Image Compulsive Actions and Body Image Avoidance Scales. Poster session presentation at the meeting of the Association for Behavioural and Cognitive Therapies, New York, NY.
Reference to software:
Coon, E., Berndt, M., Jan, A., Svyatsky, D., Atchley, A., Kikinzon, E., Harp, D., Manzini, G., Shelef, E., Lipnikov, K., Garimella, R., Xu, C., Moulton, D., Karra, S., Painter, S., Jafarov, E., & Molins, S. (2020, March 25). Advanced Terrestrial Simulator (ATS) v0.88 (Version 0.88). Zenodo. https://doi.org/10.5281/zenodo.3727209.

Video

Elsevier accepts video material and animation sequences to support and enhance your scientific research. Authors who have video or animation files that they wish to submit with their article are strongly encouraged to include links to these within the body of the article. This can be done in the same way as a figure or table by referring to the video or animation content and noting in the body text where it should be placed. All submitted files should be properly labeled so that they directly relate to the video file's content. In order to ensure that your video or animation material is directly usable, please provide the file in one of our recommended file formats with a preferred maximum size of 150 MB per file, 1 GB in total. Video and animation files supplied will be published online in the electronic version of your article in Elsevier Web products, including ScienceDirect. Please supply 'stills' with your files: you can choose any frame from the video or animation or make a separate image. These will be used instead of standard icons and will personalize the link to your video data. For more detailed instructions please visit our video instruction pages. Note: since video and animation cannot be embedded in the print version of the journal, please provide text for both the electronic and the print version for the portions of the article that refer to this content.

Data visualization

Include interactive data visualizations in your publication and let your readers interact and engage more closely with your research. Follow the instructions here to find out about available data visualization options and how to include them with your article.

Supplementary material

Supplementary material such as applications, images and sound clips, can be published with your article to enhance it. Submitted supplementary items are published exactly as they are received (Excel or PowerPoint files will appear as such online). Please submit your material together with the article and supply a concise, descriptive caption for each supplementary file. If you wish to make changes to supplementary material during any stage of the process, please make sure to provide an updated file. Do not annotate any corrections on a previous version. Please switch off the 'Track Changes' option in Microsoft Office files as these will appear in the published version.

Large data tables and long proofs of theorems should also be treated as supplementary data.

Research data

This journal encourages and enables you to share data that supports your research publication where appropriate, and enables you to interlink the data with your published articles. Research data refers to the results of observations or experimentation that validate research findings, which may also include software, code, models, algorithms, protocols, methods and other useful materials related to the project.

Below are a number of ways in which you can associate data with your article or make a statement about the availability of your data when submitting your manuscript. If you are sharing data in one of these ways, you are encouraged to cite the data in your manuscript and reference list. Please refer to the "References" section for more information about data citation. For more information on depositing, sharing and using research data and other relevant research materials, visit the research data page.

Data linking
If you have made your research data available in a data repository, you can link your article directly to the dataset. Elsevier collaborates with a number of repositories to link articles on ScienceDirect with relevant repositories, giving readers access to underlying data that gives them a better understanding of the research described.

There are different ways to link your datasets to your article. When available, you can directly link your dataset to your article by providing the relevant information in the submission system. For more information, visit the database linking page.

For supported data repositories a repository banner will automatically appear next to your published article on ScienceDirect.

In addition, you can link to relevant data or entities through identifiers within the text of your manuscript, using the following format: Database: xxxx (e.g., TAIR: AT1G01020; CCDC: 734053; PDB: 1XFN).

Data statement
To foster transparency, we encourage you to state the availability of your data in your submission. This may be a requirement of your funding body or institution. If your data is unavailable to access or unsuitable to post, you will have the opportunity to indicate why during the submission process, for example by stating that the research data is confidential. The statement will appear with your published article on ScienceDirect. For more information, visit the Data Statement page.

After acceptance

Proofs

One set of page proofs (as PDF files) will be sent by e-mail to the corresponding author (if we do not have an e-mail address then paper proofs will be sent by post) or a link will be provided in the e-mail so that authors can download the files themselves. To ensure a fast publication process of the article, we kindly ask authors to provide us with their proof corrections within two days. Elsevier now provides authors with PDF proofs which can be annotated; for this you will need to download the free Adobe Reader, version 9 (or higher). Instructions on how to annotate PDF files will accompany the proofs (also given online). The exact system requirements are given at the Adobe site.
If you do not wish to use the PDF annotations function, you may list the corrections (including replies to the Query Form) and return them to Elsevier in an e-mail. Please list your corrections quoting line number. If, for any reason, this is not possible, then mark the corrections and any other comments (including replies to the Query Form) on a printout of your proof and scan the pages and return via e-mail. Please use this proof only for checking the typesetting, editing, completeness and correctness of the text, tables and figures. Significant changes to the article as accepted for publication will only be considered at this stage with permission from the Editor. We will do everything possible to get your article published quickly and accurately. It is important to ensure that all corrections are sent back to us in one communication: please check carefully before replying, as inclusion of any subsequent corrections cannot be guaranteed. Proofreading is solely your responsibility.

Offprints

The corresponding author will, at no cost, receive a customized Share Link providing 50 days free access to the final published version of the article on ScienceDirect. The Share Link can be used for sharing the article via any communication channel, including email and social media. For an extra charge, paper offprints can be ordered via the offprint order form which is sent once the article is accepted for publication. Corresponding authors who have published their article gold open access do not receive a Share Link as their final published version of the article is available open access on ScienceDirect and can be shared through the article DOI link.

Author inquiries

Visit the Elsevier Support Center to find the answers you need. Here you will find everything from Frequently Asked Questions to ways to get in touch.
You can also check the status of your submitted article or find out when your accepted article will be published.