PONE-D-20-14789

On the connection between real-world circumstances and  online player behaviour: the case of EVE Online

PLOS ONE

Dear Dr. Ryckebusch,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please note that references suggested by reviewers could be ignored.

Please submit your revised manuscript by Sep 13 2020 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

We look forward to receiving your revised manuscript.

Kind regards,

Jichang Zhao, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. Please include a brief description in your methods section of how you accessed/collected the data, and how your full dataset can be accessed by future researchers.

3. Please remove your figures from within your manuscript file, leaving only the individual TIFF/EPS image files, uploaded separately.  These will be automatically included in the reviewers’ PDF.

4. Thank you for stating the following financial disclosure:

'The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.'

At this time, please address the following queries:

1. Please clarify the sources of funding (financial or material support) for your study. List the grants or organizations that supported your study, including funding received from your institution.
2. State what role the funders took in the study. If the funders had no role in your study, please state: “The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.”
3. If any authors received a salary from any of your funders, please state which authors and which funders.
4. If you did not receive any funding for this study, please state: “The authors received no specific funding for this work.”

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

Additional Editor Comments (if provided):

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Review report for “On the connection between real-world circumstances and online player behaviour: the case of EVE Online” by Belaza et al.

This paper studies the connection between real-world circumstances and behaviors of online players by a case study of the EVE Online game. Specifically, the authors explored the influence of the real-world context in which players live on their in-game behavior. They found a negative relation between in-game aggressiveness and real-world aggressiveness in the players country of residence, showing that players experiencing violence in daily life have a tendency to be less aggressive in online games. Moreover, players from more peaceful countries tend to maintain more friends relatively to those living in more violent countries. The authors also found some correlations between in-game trading and real-world variables reflecting the macroeconomic context where players live, for example, there are correlations between unemployment rates and money-conscious in-game trading behavior.

Understanding the connections between real-world circumstances and online behaviors is an interesting and important issue, which has implications for better understanding human behaviors and designing better experiments with a variety of settings. I think this paper considers an interesting research question, the results and analyses are convincing, and the structure of the paper is good. In my view, this paper deserves a final publication. In the following, I would like to provide some suggestions and comments, which may be helpful for the authors to further strength their paper.

1. In the abstraction section, the authors presented that “Virtual worlds involving social and economic interactions are particularly useful to test social and economic theories”. I think this is particularly interesting considering that analyzing behaviors in virtual worlds has relatively low cost and virtual worlds are more flexible in implementing experiments to test social and economic theories if they are well representations of offline worlds. The authors also mentioned in the first paragraph of the introduction section that “A major question, however, is whether the data extracted from virtual worlds are representative enough to study real-world socioeconomic phenomena and whether they capture real-world human behaviour”. There are some previous works that can better support the authors’ narratives in related content, for example, using online posts and mobile communications to infer individual economic status [Luo, S., Morone, F., Sarraute, C., Travizano, M., & Makse, H. A. (2017). Inferring personal economic status from social network location. Nature communications, 8(1), 1-7], and infering socioeconomic status from large-scale online data sources [Gao, J., Zhang, Y. C., & Zhou, T. (2019). Computational socioeconomics. Physics Reports, 817, 1-104]. The authors are suggested to cover a relative broad branch of literature and present a more general introduction of the background of this paper.

2. On page 2, the authors presented that “Using EVE data, Carter has conducted a study of the use of propaganda during war times as an essential factor for maintaining the morale [28]”. It would be better to keep the typical citing format as the authors used. That is “Using EVE data, Carter [28] has conducted a study xx”. On page 3, the authors presented that “To play EVE Online, a player needs to pay a subscription fee of 15 USD or 15 EUR per month, or spend the equivalent amount by buying an item (called PLEX) inside the game”. I am wondering how the subscription fee will affect the enrollments of the EVE Online. For some low-income countries, the sampling rate of all population may be different. It would be necessary to present a new figure showing the number of users for each country, and the share to all population in each country. I am wondering if the sampling bias will affect the observations.

3. On page 3, the authors presented that “The analysis presented in this work is based on collected EVE Online data from December 2011 to December 2016 (61 months) for the trade activity and the year 2016 for the social and economic activity”. It seems that the authors used cumulative data across their study, however, I am wondering if there are any temporal changes of these patterns observed in this paper, for example, the correlations between online game behavioral features and real-world economic indicators in the year 2014, and how the results evolve over time. Regarding the two variables: (i) Added As Negative" and (ii) Added As Positive, I think there are also temporal changes, for example, a player can be added as negative and as positive at different periods considering the online game is a dynamitic systems and friendships among players can change quickly. I am wondering how the authors capture these evolving characteristics.

4. On page 4, the authors presented that “The latter three activities result in the generation of an in-game item that we transform into a numeric value using the market prices. Data are aggregated on a weekly basis, creating a specific player profile per week”. I think it remains unclear how the authors did the transformation into a numeric value. The authors are suggested to add more explanations to this point. On page 5, the authors presented that “Finally, the player's profile is normalised by the sum of the eight adimensional measures of the in-game activities”. I am wondering if the method of normalization may affect the results and if the sum of the eight adimensional measures is treating measures with equal weights.

5. In Table 3, the authors presented country profiles for selected countries. I noticed that most of these countries are western countries. Maybe it is better to include some Eastern and Asian countries as well considering a diverse set of cultural backgrounds. In Fig 1, the authors presented the in-game similarity between countries. First, it would be better to show all country names in the x-axis as well. Second, it would be better to reverse the color scheme, where red indicates positive value and blue indicates negative values.

6. In Table 5 and Table 6, it would be better to list Intercept blow other control variables but above the R2. Listing the variables of most interests in the top of the tables is a tradition. Also, No. observations should be listed above R2. In addition, the authors presented some convincing correlations among online behaviors and offline socioeconomic status. Yet, I am wondering if it is possible to identify some causal relationships using instrumental variables. It would be not easy due to the observational data, but I am wondering the possibility. It would be nice to add some related discussions in the discussion section.

7. The authors found that “players from safer countries behave on average more aggressively towards other players in the virtual world than players from unsafer countries”. I am wondering if there are social and psychological explanations for this observation. In the reference section, it would be better to presented the full journal name for PNAS as “Proceedings of the National Academy of Sciences, U.S.A.”. For other references, they are in very good shape of citing format.

Reviewer #2: In this manuscript, authors analyze the influence of the real-world context in which players live on their in-game behavior. This work is of great interests, and the analysis is solid. I would recommend publication after the authors make proper minor modifications.

1 It is better to highlight the contributions of this work and the difference between this work and the previous studies in the introduction.

2 About the in-game country profile, data are aggregated on a weekly basis, creating a specific player profile per week. And the variables on social interaction, aggressiveness and production activity are calculated by the absolute quantity. I think the times players in different countries spend on online game may varies. Therefore, it is better to use the number of activities per unit of online time to calculated the variables, right?

3 “For the country profile, the average of all the profiles of the players belonging to that country is taken and normalized by the standard score of all countries with at least 15 players in EVE online.

”. Please provide more statistic analysis to support the threshold (15 players).

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

On the connection between real-world circumstances and  online player behaviour: the case of EVE Online

PONE-D-20-14789R1

Dear Dr. Ryckebusch,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Jichang Zhao, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments: