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Summary 

This report forms part of our work to conduct cost-effectiveness analyses of interventions and charities based on their effect on subjective wellbeing, measured in terms of wellbeing-adjusted life years (WELLBYs). This report aims to achieve six goals.

1. Update our original meta-analysis of psychotherapy in low- and middle-income countries.

In our updated meta-analysis, we performed a systematic search and collected 74 (previously 39) randomised control trials (RCTs). We find that psychotherapy improves the recipient’s wellbeing by 0.7 standard deviations (SDs), which decays over 3.4 years, and leads to a benefit of 2.69 (95% CI: 1.54, 6.45) WELLBYs. This is lower than our previous estimate of 3.45 WELLBYs (McGuire & Plant, 2021b) primarily because we added a novel adjustment factor of 0.64 (a discount of 36%) to account for publication bias.

2. Update our original estimate of the household spillover effects of psychotherapy.

We collected 5 (previously 2) RCTs to inform our estimate of household spillover effects. We now estimate that the average household member of a psychotherapy recipient benefits 16% as much as the direct recipient (previously 38%). See McGuire et al. (2022b) for our previous report-length treatment of household spillovers.

3. Update our original cost-effectiveness analysis of StrongMinds, an NGO that provides group interpersonal psychotherapy in Uganda and Zambia.

We estimate that a $1,000 donation results in 30 (95% CI: 15, 75) WELLBYs, a 52% reduction from our previous estimate of 62 (see our changelog website page). The cost per person treated for StrongMinds has declined to $63 (previously $170). However, the estimated effect of StrongMinds has also decreased because of smaller household spillovers, StrongMinds-specific characteristics and evidence which suggest smaller than average effects, and our inclusion of a discount for publication bias.

The only completed RCT of StrongMinds (another RCT is underway) is the long anticipated RCT of StrongMinds by Baird and co-authors, which has been reported to have found a “small” effect. However, this study is not published, so we are unable to include its results and unsure of its exact details and findings. Instead, we use a placeholder value to account for this anticipated small effect as our StrongMinds-specific evidence¹We use a study that has similar features to the StrongMinds intervention and then discount its results by 95% in the expectation of the Baird et al. study finding a small effect. Note that we do not only rely on StrongMinds-specific evidence in our analysis but combine charity-specific evidence with the results from our general meta-analysis of psychotherapy in a Bayesian manner..

4. Evaluate the cost-effectiveness of Friendship Bench, an NGO that provides individual problem solving therapy in Zimbabwe.

We find a promising but more tentative initial cost-effectiveness estimate for Friendship Bench of 58 (95% CI: 27, 151) WELLBYs per $1,000. Our analysis of Friendship Bench is more tentative because our evaluation of their programme and implementation has been more shallow. We plan to evaluate Friendship Bench in more depth in 2024.

5. Update our charity evaluation methodology.

We improved our methodology for combining our meta-analysis of psychotherapy with charity-specific evidence. Our new method uses Bayesian updating, which provides a formal, statistical basis for combining evidence (previously we used subjective weights). Our rich meta-analytic dataset of psychotherapy trials in LMICs allowed us to predict the effect of charities based on characteristics of their programme such as expertise of the deliverer, whether the therapy was individual or group based, and the number of sessions attended (previously we used a more rudimentary version of this). We also applied a downwards adjustment for a phenomenon where sample restrictions common to psychotherapy trials inflate effect sizes. We think the overall quality of evidence for psychotherapy is ‘moderate’.

6. Update our comparison to other charities

Finally, we compare StrongMinds and Friendship Bench to GiveDirectly cash transfers, which we estimated as 8 (95% CI: 1, 32) WELLBYs per $1,000 (McGuire et al., 2022b). We find here that StrongMinds is 30 (95% CI: 15, 75) WELLBYs per $1,000. Hence, comparing the point estimates, we now estimate that StrongMinds is 3.7x (previously 8x) as cost-effective as GiveDirectly and Friendship Bench is 7.0x as cost-effective as GiveDirectly.

These estimates are largely determined by our estimates of household spillover effects, but the evidence on these effects is much weaker for psychotherapy than cash transfers. It is worth noting that if we only consider the effects on the direct recipient, the cost-effectiveness of StrongMinds (10x) and Friendship Bench (21x) would become much more favourable compared to GiveDirectly, but less so to other interventions like anti-malaria bednets. We also present how sensitive these results are to the different analytical choices we could have made in our analysis.

This is a working report, and results may change over time. We welcome feedback to improve future versions.

Notes

Author note: Joel McGuire, Samuel Dupret, and Ryan Dwyer contributed to the conceptualization, investigation, analysis, data curation, and writing of the project. Michael Plant contributed to the conceptualization, supervision, and writing of the project. Maxwell Klapow contributed to the systematic search and writing.

Reviewer note: We thank, in chronological order, the following reviewers: David Rhys Bernard (for trajectory over time), Ismail Guennouni (for multilevel methodology), Katy Moore (general), Barry Grimes (general), Lily Yu (charity costs), Peter Brietbart (general), Gregory Lewis (general), Ishaan Guptasarma (general), Lingyao Tong (meta-analysis methods and results), Lara Watson (communications).

Charity evaluation note: We thank Jess Brown, Andrew Fraker, and Elly Atuhumuza for providing information about StrongMinds and for their feedback about StrongMinds specific details. We also thank Lena Zamchiya and Ephraim Chiriseri for providing information about Friendship Bench.

Appendix note: This report will be accompanied by an online appendix that we reference for more detail about our methodology and results. The appendix is a working document and will, like this report, be updated over time.

Updates note: This is the first draft of a working paper. New versions will be uploaded over time.