Evaluating the Accuracy of Gridded Population Estimates in Slums: A Case Study in Nigeria and Kenya

Round 1

Reviewer 1 Report

Review

Thank you for your important research. The paper reads very interesting and I am convinced of the necessity of your work. However, I have some remarks, which I think will enhance your contribution:

Abstract

- There should be no space between the number and its corresponding symbol. However, place a space between the number and an abbreviated unit of measurement (100 x 100 m). Be consistent. Sometimes you spell out the unit, sometimes you abbreviate. However, in tables, do not put a space between the figure and its symbol, or between the figure and its unit of measurement.

- Please, provide quantitative results in the abstract

Introduction

- Please, provide research questions and answer them in the conclusion section

- Please, add a brief overview of the structure of your paper in the end of your introduction

Materials and Methods

- Please, discuss briefly why you have chosen two Nigerian ROIs. Isn’t it possible to find “more consolidated” cities in e.g. South African countries?

- Please, check again the information on the Badmos Slum Map. She and her colleagues used SLEUTH to modell the FUTURE of Lagos. The object based image analysis classification process is described in Badmos, O.S., Rienow, A., Callo-Concha, D., Greve, K., Jürgens, C. (2018): Urban Development in West Africa—Monitoring and Intensity Analysis of Slum Growth in Lagos: Linking Pattern and Process. In: Remote Sensing 10(7), 1044-1066. https://doi.org/10.3390/rs10071044. Please, refer to that paper, too.

- Please, explain briefly why you have waived Pearson correlation coefficient and decided to make use of MAE, RMSE, bias, and MF

- Please, explain how the gridded population maps have been originally validated by their developers and add the validation information to Fig. 4

Conclusion

- Please, answer your research questions

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

A clear and appropriate evaluation of the gridded population estimates to studie slums.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Very good and interesting paper. I thought that the paper was sound and it included critical information on the slums. Here are my suggestions for change:

Abstract: Contains mostly background, needs more information on statistical and spatial methodology, selected results, and conclusions.

Introductions: I noticed that introduction did not include much detail on study objectives, research questions, and hypotheses. In a research article, I tend to favor quality over quantity of sources, limiting the number of sources to a maximum of 50 sources, unless the paper is a meta-analysis, and prioritizing peer-reviewed sources that are 5 year or later. This allows the paper to be based on current research, which are more likely to be cited by other authors.

Methods: Was the study approved by an ethics committee, this needs to be stated in the paper in the methods section. I found that the statistical methods section needs to include more detail on analyses performed, including an adjusted multivariate analysis, possibly adjusting for age, sex, etc. Unclear why this section included results? Also why is there no information of geographic methods performed in a separate subsection.

Results: Tables and Figures need to stand alone and inserted into the manuscript, in addition to being images, which should be 300 dpi. If the table/figure has multiple parts it needs to be lettered. I had a hard time rationalizing the table shells of data, and captions needed more context, including information on what the acronyms signify, as a footnote. I also would have like to have p-values in tables if possible. Also this paper is mostly not adjusted and I suggest adding a multivariate model as table 5. I also would have liked more information on what the tables and figures, instead of just citing the tables/figures. It would have been nice to have subsections in this section.

Discussion: I also noticed that there was little attention to limitations, recommendations, and significance of study, with each being a distinct subsection (i.e., limitations outlines methodological and practical issues with the paper; recommendation outlines areas for future research; significance outlines areas of change). I also would have like to include more information relating your study to international literature and spatial analyses literature.

Conclusions: It should conclude a paper, based on the results and should not read as a recommendations section, with no references in this section.

References: I would have liked if you included hyperlinks or DOIs to the reference section, and including more recent sources. I also found that the reference section uses an inconsistent format, which could have been corrected by using a reference management system, such as open-source Zotero (https://www.zotero.org/), which provides an add-in to Microsoft Word and modern browsers.

Other concerns: This paper contains too much information. I recommend breaking it down to multiple papers. I could see 3-4 papers alone for this manuscript.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Thanks for addressing my concerns about your manuscript to the best of your ability. I noticed that you mislabeled your tables, with the removal of table 3, to the appendix, table 5, should now be table 4. Currently, there is no Table 4, in the manuscript.

Author Response

Dear Reviewer 3,

Many thanks for catching and flagging our misnumbered Table 5. We have now corrected this.

Best, Dana R. Thomson