PONE-D-20-15278

Accounting for Drinking Water Quality in Measuring Multidimensional Poverty in Ethiopia

PLOS ONE

Dear Dr. Ambel,

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.

Three reviewers consistently point to issues regarding the proper justification and measurement of the proposed Multidimensional Poverty Index. All of their observations should be addressed in a revised submission.

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PLOS ONE

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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

Reviewer #3: Yes

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

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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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

Reviewer #3: Yes

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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

Reviewer #3: Yes

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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: This study clearly shows that accounting for drinking water quality in measuring multidimensional poverty increases the headcount of the latter. The paper is focused and easy to follow.

The effect of accounting for drinking water quality on multidimensional poverty has qualitative and quantitative aspects. Qualitatively, using a more precise measure of an indicator (safe water in this case) is likely to make headcount poverty always higher. Reading this paper doesn’t add much insight in terms of the qualitative effect and hence this aspect doesn’t justify the paper well. That is, the conclusion that “reliance on reported use of different types of water source as the measure of drinking water access can greatly understate poverty” is all too obvious, even without doing such a study.

The quantitative measure of the effect (that poverty increases 5-13 pp), on the other hand, may suffer from several limitations, some mentioned by the author(s) and others in my comments below.

One, data were collected May-July, the wet months in most parts of Ethiopia. E.coli contamination is likely to be much higher during these months, since even relatively safer sources will be flooded. This is likely to make the figures unreliable, as having a survey a months earlier or later might affect the results.

Two, the sampling units are households but safety of drinking water at source is the same for people who fetch water from the same river. This creates clusters of households which will have similar measures of water quality. Another way of thinking about this is that sampling over households and sampling over sources will not be the same.

Three, the claim that “all [households and sources] are statistically representative nationally” is too strong, considering the fact that water quality can be sensitive to changes such as rain and flooding, topography, culture and so forth.

Other comments:

A small section describing poverty, access to water, rural-urban differences and natural environmental differences would give context to the results.

Page 4, “It is also an effective tool for targeting.” Not all potential readers of this paper will understand ‘targeting’ the same way the authors think about it.

Page 7, “The percentages are weighted.” It may not be clear how and why.

Table 1,

Child Mortality: children dying of other natural causes included.

Years of schooling: no 10 year-old is old enough to have completed 6 years of schooling.

Cooking fuel: is a household that uses charcoal to make coffee included? This is important, given the cultural significance of making coffee.

Reviewer #2: This paper investigates the accuracy of the Multidimensional Poverty Index (MPI) by replacing one of the measurements in the index (water source type) to a more comprehensive measure (safely managed drinking water services, defined as water free from E. coli contamination). By using this new measure of MultiDimensional Poverty (MPD) on data from Ethiopia the authors find that the Multidimensional Poverty Headcount (MPH) increase by 13 percentage points on the national level, or at least by 5 percentage points using a measure of E. coli risk. This can be translated to between 5-13 million more people in MDP.

The paper does not use any advanced statistical methods, but asks a relatively straightforward question: do we measure MPD correctly?

I share the authors conviction that it is important with good measurements on such an important topic as poverty, but I do lack a discussion in the paper on the take-home message from the paper. While I have no doubt that water quality is very important – especially for the very poor – I am not necessarily convinced that we should redefine the MPI, which is the implicit message I read in the paper. We can define “poverty” how we like; the relevant question to ask of any measurement is that of validity and reliability. An even more strict definition of (good) water quality than the authors use would no doubt increase the MPH in Ethiopia further. Having access to improved water sources (even if not necessarily “clean”), is likely to be better than not having access to it at all. Maybe this is the correct definition? If not, why?

Thus, the fundamental question I ask is: Does it matter? I do think that the paper would be much improved if it gives a more thorough discussion on why this new MPI definition is to be preferred. Are there any policy recommendations etc.?

The authors should clarify the discussion on subjective or objective measure of water, as this is important (which is clear from the discussion and conclusion). On page 15 (line 298-299) the authors write “replacing the subjective water indicator with a more objective measure…”. On page 5 (line 91) the reader gets the impression that the standard way of measuring is objective, but possibly not a good measure as it only focus on whether the water source is improved or not.

* The tables should present the number of observations.

* The share of the population living in different areas (urban, rural etc.) should be presented.

Reviewer #3: This paper estimates multidimensional headcount poverty in Ethiopia. The authors find that using a direct measure of water quality (whether E. coli is present at the water source of the household) instead of the more commonly used survey measure of access to drinking water (whether the household has access to an improved water source) increases multidimensional headcount poverty by at least 5 percentage points.

This paper shows the importance of measurement. Thus, two revisions could improve this paper:

1. The authors should be clearer about the exact measures related to drinking water. The authors refer to a safely managed water source, which I believe is measured as no E. coli present at the water source of the household. The authors should explicitly state this so that the text reads more clearly. For the measure of access to drinking water, defined as whether the household has access to an improved water source, the authors refer to this measure as self-reported. Who reports this measure and how is the question asked?

2. The implication of the two measures is that the direct measure of the presence of E. coli is accurate while the self-reported measure of access to an improved water source is measured with error. To support this implication, how accurate are the direct measurements in reflecting the presence of E. coli throughout the year? Is E. coli the most harmful contaminant in the drinking water in Ethiopia? Could the self-reported measure of access to an improved water source reflect water quality based on other contaminants besides E. coli? The authors address the limitations briefly in the last paragraph of the Discussion section. However, since measurement is the important theme of the paper, these limitations should be further discussed. Evidence from other studies could be used to describe whether these limitations are likely to be minor and not change the main conclusions from this paper.

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

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Accounting for Drinking Water Quality in Measuring Multidimensional Poverty in Ethiopia

PONE-D-20-15278R1

Dear Dr. Ambel,

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.

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Kind regards,

Francisco X Aguilar

Academic Editor

PLOS ONE

Additional Editor Comments: Authors shall address minor issues raised during the last iteration.

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

Reviewer #3: All comments have been addressed

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2. 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 #2: Yes

Reviewer #3: Yes

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

Reviewer #2: Yes

Reviewer #3: Yes

**********

4. 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 #2: Yes

Reviewer #3: Yes

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5. 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 #2: Yes

Reviewer #3: Yes

**********

6. 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 #2: I thank the authors for their reply and revised manuscript.

I have a minor point that I noticed during the re-reading of the manuscript. In Table 2 and Table 6, I do believe that it should be an "or" instead of an "and" in the last column header. I.e., "No safely managed OR free from contamination at point of use". As it stands now, the numbers makes no sense as an "and" is more strict than an "or", hence "H (%)" should be lower -- not higher. Compare with Table 3. To avoid confusion, it seems best to use the column header from Table 3 in Table 2 and 6.

Reviewer #3: (No Response)

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7. 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 #2: No

Reviewer #3: No