Peer Review History

Original SubmissionNovember 2, 2021
Decision Letter - Brendan Fisher, Editor, Juan Uribe Toril, Editor

PSTR-D-21-00042

A meta-analysis on the adoption of agricultural technology in Sub-Saharan Africa

PLOS Sustainability and Transformation

Dear Dr. Arslan,

Thank you for submitting your manuscript to PLOS Sustainability and Transformation. After careful consideration, we feel that it has merit but does not fully meet PLOS Sustainability and Transformation'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.

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Juan Uribe Toril

Academic Editor

PLOS Sustainability and Transformation

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does this manuscript meet PLOS Sustainability and Transformation’s publication criteria? Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe methodologically and ethically rigorous research with conclusions that are appropriately drawn based on the data presented.

Reviewer #1: Partly

Reviewer #2: Yes

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

Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: 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: Review of

A meta-analysis on the adoption of agricultural technology in Sub-Saharan Africa

This is an interesting and well written manuscript studying factors promoting and hindering the adoption of agricultural technology – in a very broad sense – in Sub-Saharan Africa. The paper analyses seem well conducted and all figures are interesting and informative. However, there are some major and minor issues that need the attention of the authors. Nonetheless I’m confident that these are all addressable in the scope of a careful manuscript revision.

Major points

Phrasing around agricultural technologies

I understand the phrasing around agricultural technologies, but coming from a slightly different discipline I find it a bit hard to grasp. Basically these technologies are now framed as technologies largely coming from the outside (like synthetic fertilizers) but many of these technologies may be traditionally used for generations (thinking about crop rotation or agroforestry). Making this more clear in the introduction would make the manuscript more accessible to an multipdisciplinary readership.

In this context, it may also be important to address possible negative effects of agricultural technologies in the discussion section – something that is currently entirely missing. Here, an obvious one may be possible negative effects of pesticides on biodiversity and ecosystem services, but obviously one could think of others depending on the technology.

Very broad determinant categories

The factors grouped within some of the determinant categories are very broad. This is particularly the case for ‘socio-demographic’ and ‘bio-physical’, especially since one could think of different hypotheses (+/-) for each of these factors. For example female household head may result in different hypotheses to ‘more children’, or ‘plot fertility’ and ‘land degradation’ go per se into different direction. So the result that these categories have sometimes positive and sometime negative implication is very obvious and possibly mainly due to the meta-analysis methodology rather than due to heterogenous effects and context-dependency.

For the bio-physical, I would suggest splitting in ‘favourable bio-physical conditions’ and ‘unfavourable bio-physical conditions’. That way you would get rid of this issue quite easily? For the socio-demographic category I unfortunately don’t see an easy fix since this cannot easily be split in two unless you would have fix hypothesis for each outcome (like socio-demographic factors favouring/disfavouring adoption) based on the hypotheses you already have? If this is not possible, the issue would warrant an in-depth discussion / limitations section in the discussion.

In any case, this issue needs attention in a revision.

Making the manuscript more policy-relevant

It would be really nice to finish the discussion with entry points for policy, thinking about which of the categories can be influenced by policy and how. For example the biophysical variables may be important but would be hard to influence on the local scale (the farm is just where it is), so it’s not a suitable entry point. Similarly, ‘wealth’ maybe hard to address for an NGO. Instead, others, like the access to training/knowledge may be influenced by smart policies. So just because something has a positive effect on adoption, it does not mean that policy can influence adoption through that something. So far I miss this topic from the discussion and I believe it could give the whole thing a very positive and interesting twist (maybe also check recent literature on leverage points in sustainability science / land system science).

Organization of manuscript

As far as I understand, PLOS SUST TRANS is open to various formats but usually publishes papers in the classic Intro – Methods – Results – Discussion – (Conclusion) – References format. I think for this paper, having the results first works ok but maybe putting the methods first would be better? That way some of the repetition of methods at the beginning of the results becomes obsolete and the methods are clear from the beginning? Also this would solve the issue with Box 1: this element is currently a bit lost in the results and referred to from the Methods in the end which is a bit odd, so placing that in the Methods that would come earlier may be a better approach?

Explanation of all hypotheses including references

I like the idea of the hypotheses including direction. However, these hypothesis are poorly documented. In the methods, it is written that these are based on literature but I miss the actually written out hypotheses including documentation (i.e. references) for each hypotheses, both in the main text and the supplementary material. This seems really important to me and such written out hypotheses may not only benefit this manuscript but could also inspire future research.

Better documentation study identification

It would be nice to see in Table S2 how many papers were excluded for which reason (just an additional column). Also quite a few details are missing for the literature search, at the moment it is not replicable. This includes language (assume only English?), which parts of Web of Science (multiple collections there), which subscription (not all Universities/Organisations see the same results) etc. Please refer to best practice guidelines for documenting this better. This also includes a statement of the search string applied, just referring to another paper is not enough from my point of view.

No data availability

The statement that data can be made available upon request is insufficient in my opinion, especially since the database could be amended and further analyzed in the future, representing an important resource for researchers.

If you plan further publications with the data, you can upload all data already now under an embargo so that the data becomes automatically available at a given date in the future. If I remember correctly, releasing the data underlying articles is also a requirement of the journal.

Minor points

Claim on coding precision without description how this was assessed

Somewhere there was a claim on ‘relatively high coding precision’ or something like that, without going more into detail on how high and how this was assessed (multiple coders for a subset of the studies?). Please give information on the methods for assessing this and on the results of this analysis.

Beginning of abstract

The abstract starts with a specificity on the year 2020 but the paper would be published in 2022 and will (hopefully!) be read for many years to come, so maybe consider starting the abstract with a broader non-year-specific sentence?

Authors’ summary

The authors’ summary is currently largely a repetition of the abstract. Instead, it would be nice if the summary would be complementary to the abstract, giving a slightly different and possibly more accessible angle.

Number of articles confusing in beginning 168/1113

In line 168, it sound like 1113 studies were included, but in the methods it becomes clear that 168 studies met the inclusion criteria. That is totally ok and normal, but this must become crystal clear early on (and is well done in the abstract), so definitely put the 168 number into this section.

Clarifications in methods sections

In parts, the method section is hard to understand with out reading the Rosenstock et al. paper (especially the first part up to line 372). Please carefully go through this section and make sure that this is fully understandable for readers without falling back on that reference. This also includes a repetition of the search string, at least in the supplementary material.

Inconsistent use of terms

In the supplements, you talk about ‘socio-demographic factors’ and in the main text about ‘social capital’. I assume this is the same? Similarly, sometimes its cases, sometimes datapoints, again assuming this is the same? Please go through all terms used and make sure they are consistently used, also between Supplementary Material and Main Manuscript.

Pseudoreplication within same underlying study

Did you somehow address pseudo replication in the selection of studies, the data extraction, or the data analyses? I mean the same study may include several analyses, where they then counted separately?

If not addressed quantitatively or excluded, this would also be a key thing to highlight in the limitations section/paragraph.

Figures

Figure 1

Very nice and informative. For the top left, however, there are colours in the legend that are not used in the squares, presumably due to <100 cases. Consider adding smaller squares too? Or some other solution, but having stuff in the legend which is not in the figure is wrong and confusing.

Also what are the cases actually? This is totally unclear at this point – please make this clear in an improved figure legend, possibly also linking to the various elements of figure 1 using A, B, C. This also links to below – here you report data points (line 123), are these the cases? Please clarify and revise.

For the map, it is currently unclear whether a country had zero studies or whether a country was not considered ‘Sub-Saharan Africa’. Of course for the southern African countries this is obvious, but for example for Chad this is unclear. So would be nice to have 0 studies in a different colour to ‘non-SSA’.

Figure 2

Nice! For the different categories, consider adding a direction (links to Major point one), like “Larger labor availability” etc. Also I would suggest to write out n.s. and make the + / - much larger (consider an icon?) to make the figure more intuitive and easier to read.

Figure 3

The colours for positive and negative are very similar suggesting some kind of gradient. However, given this is opposing, I would find two contrasting colours more intuitive.

Also it would be better to sort the graph from the top to the bottom according to the estimate rather than the upper end of the confidence interval.

Figure 4

Is there any specific reason why the design changes over Figure 3? Like why are there no point estimates and confidence intervals and instead only the intervals? Also again consider directions (more / less etc.) for each entry on the left.

Line-by-line

31 Maybe try to rephrase so that one does not need to know SDG 1 and SDG 2 by heart?

43 proffer � offer?

66 The sentence “Agricultural productivity in Sub-Saharan Africa (SSA) is currently about 50% that of other low and middle income countries” sounds as if SSA is a country, please rephrase.

73 yields only doubled � is this per unit of land or overall? Important to distinguish this here to set the stage for the following sentences.

383 Reference missing

387 What does 1925 stand for?

Thanks for the opportunity to review this interesting manuscript.

Dr. Dominic A. Martin

Reviewer #2: Review of “A meta-analysis on the adoption of agricultural technology in Sub-Saharan Africa.”

1. Summary of the research

Adoption of agricultural technologies among rural farmers in Sub Saharan Africa (SSA) is very important to increase productivity and ensure the success of the United Nations Sustainable Development Goals (SDG) 1 and 2. Arslan and co-authors made a great effort to conduct a meta-analysis of peer reviewed papers on adoption of technologies mainly from Ethiopia, Kenya, and Nigeria, and other countries in the SSA. In general, the findings narrated in this meta-analysis paper sound very interesting. The paper is also well written, easy to read and should be published. However, I have some observations that I would like to share with the authors with the aim to improve the paper.

(i) Introduction

The introduction section is well written and gives the reader a better understanding on why the study was conducted. The research question on what determines the adoption of 97 agricultural technologies in SSA from 30 years of published research is important to investigate. I particularly like the goal of the study which is to provide guiding principles for adoption with the aim to inform policy. The authors referred to individual adoption studies that tend to provide results that are specific to particular farmers, technology or location. I think this type of specific studies are also needed to provide targeted agricultural solutions to resource poor farmers in SSA and should be encouraged by donors, policy makers and the scientific community.

(ii) Results

The dataset section of the paper is clear but, I would like to have an explanation on why the authors think that the skewed distribution of the practices in Fig1 reflects the importance of crops such as maize, rice and cassava for food security in SSA. There are other crops e.g., yam, soybean, cowpea, Banana and Plantain that are equally important for food security in SSA.

The results in figures 2 to 4 are well explained. The authors indicated that wealth is positively correlated with adoption in many studies. This is interesting to know but unfortunately most rural farmers in SSA are not wealthy and need to be supported, trained, and encouraged to adopt agricultural technologies to increase productivity.

(iii) Discussion

The discussion section is impressive. I agree with the idea of using standard ontologies for the determinants of adoption to ensure comparability across studies. This will be useful for future meta-analysis studies. Having said that, I was a bit surprised to read that no study found land tenure to be significantly associated with adoption of improved livestock practices. While this may be true depending on the location of the study, but the discussion that livestock do not require private land holdings and may be grazed on communal lands is also surprising. This is because grazing cattle in communal farmland is the source of unrest between farmers and herdsmen in most SSA countries. Perhaps this section of the discussion needs to be reviewed.

(iv) Materials and Methods

This section is clear and easy to read but I will suggest that it should be presented early in the paper. This would enable the reader to read with ease.

(v) Data Analysis

The idea of using vote count analysis in combination with sign test analysis is a major strength of the study because it helped the reader to appreciate the results

2. Minor issue

In terms of structure, I will recommend the authors to use the traditional structure of introduction, materials and methods, results, discussion, conclusions, and recommendations.

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Reviewer #1: Yes: Dominic Andreas Martin

Reviewer #2: Yes: Dr. Hope Webber

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Attachments
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Submitted filename: Review meta-analysis technology adoption SSA.docx
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Submitted filename: Review of A meta-analysis on the adoption of agricultural technology in Sub-Saharan Africa_HW.pdf
Revision 1

Attachments
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Submitted filename: Response to Reviewers_Meta-analysis technology adoption SSA.docx
Decision Letter - Brendan Fisher, Editor, Juan Uribe Toril, Editor

A meta-analysis of the adoption of agricultural technology in Sub-Saharan Africa

PSTR-D-21-00042R1

Dear Dr. Arslan,

We are pleased to inform you that your manuscript 'A meta-analysis of the adoption of agricultural technology in Sub-Saharan Africa' has been provisionally accepted for publication in PLOS Sustainability and Transformation.

Before your manuscript can be formally accepted you will need to complete some formatting changes, which you will receive in a follow-up email from a member of our team. 

Please note that your manuscript will not be scheduled for publication until you have made the required changes, so a swift response is appreciated.

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Thank you again for supporting Open Access publishing; we are looking forward to publishing your work in PLOS Sustainability and Transformation.

Best regards,

Juan Uribe Toril

Academic Editor

PLOS Sustainability and Transformation

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