DISCUSSION
We conducted a randomized controlled trial of a personalized decision support app addressing informational constraints and choice architecture in the context of health technology adoption and cross-randomized it with discounts. Given a brief and neutral summary of all methods and asked to choose which method(s) they would like to discuss, IDM clients overwhelmingly discussed only one method. In contrast, the provision of personalized rankings to SDM clients and a suggestion that they should start the discussion with the top-ranked method but also that there were other promising alternatives caused a large increase in the number of methods discussed in detail, which then led to the increased adoption of LARCs from further down the ranked list. This simple tweak in counseling caused increases in LARC uptake that were as large as the effect of providing substantial discounts under IDM. As such, we not only show that LARC uptake can be substantially increased within an existing comprehensive framework for high-quality counseling (Offering discounts was effective in increasing LARC adoptions in IDM. Overall, clients aged 20 or older were almost three times more likely to adopt a LARC at full price than adolescents, but discounts eliminated this gap (table S9). Single women were more price sensitive than married (or partnered) ones. Women in the maternity or gynecology wards, most of whom had recently given birth and who were half as likely to adopt LARCs at full price, also responded favorably to discounts. These results indicate that discounts would be better targeted to vulnerable women, who are both more likely to be liquidity- or credit-constrained and for whom unintended pregnancies are costlier. Our findings are consistent with recent evidence on the effect of subsidies on contraceptive take-up [e.g., (Without a robust measure of contraceptive concordance, we cannot definitively conclude whether clients made a better choice for themselves (inclusive of adopting no method) under SDM relative to IDM. Rather, our focus is to analyze modern contraceptive uptake in response to the personalized digital counseling intervention while also providing supporting evidence related to contraceptive concordance—including method continuation, quality of care, and client satisfaction with FP services at HGOPY. The high quality of care and client satisfaction observed in SDM, combined with low rates of method discontinuations and switching, provide suggestive evidence that adoption decisions in this counseling regime are concordant with client preferences. This tentative conclusion is not unexpected because the app’s algorithm ranks methods according to many of those same preferences and SDM causes a detailed discussion of more methods.Our study has some limitations. As discussed in the “Data” section, supporting evidence for quality of care and client satisfaction comes from participants in the adaptive trial that started immediately following the end of our study. Since this sample is exposed to exactly the same interventions and looks very similar to our study sample (table S1), we argue that it is an adequate source of data to provide supporting evidence on quality of care, client satisfaction, and method discontinuation. Similarly, we do not observe 12-month pregnancy rates (which would be reasonably defined as unintended per the inclusion criteria in our analysis of clients wishing to wait more than 12 months before becoming pregnant). However, the very high typical use effectiveness of LARCs, combined with low discontinuation rates, provide a good proxy for expected 12-month pregnancy rates. Last, our sample is composed of clients at a women and children’s hospital in Yaoundé, who differ from a random sample of women of childbearing age in the 2018 Cameroon DHS. As such, caution should be taken when applying our findings in other settings. Issues such as provider training and implementation fidelity might have particular relevance in the context of efforts to scale up.Our study speaks to the importance of one-on-one FP service integration into all primary health care services: Clients at HGOPY, a large women and children’s hospital in Cameroon, were willing to receive counseling when approached and were responsive to the targeted interventions in our study. While increasing demand for modern contraceptives by reaching women outside of health care settings is surely important, counseling current clients of clinics represents an important opportunity for reducing unintended pregnancies and increasing birth spacing. Checklists for antenatal visits, childhood vaccinations, and postpartum and post-abortion clients could all include an item to offer FP counseling to women of childbearing age. At the same time, campaigns to reach adolescent girls and young women might be successful if they can combine high-quality counseling with affordable prices. This is consistent with recent evidence from Cameroon, which showed that providing sexual and reproductive health information to adolescents at school can decrease the incidence of teenage pregnancies (The app that was developed as part of this project is easy to use, accepted by providers and clients alike, and can be easily integrated into existing practice as a job-support tool for counselors. As it was cheaply built on a survey platform, it would be affordable to adopt; as it has open source code, it is easy to adapt the underlying algorithm to accommodate different counseling approaches, other criteria to rank methods, and to collect different types of data on FP counseling; and as it can accommodate multiple languages with the use of drop-down menus, it would be convenient to deploy in settings with a diverse client population. It could also be adapted for use as a decision-support tool for clients, either in the privacy of their home (in the form of a phone app or an online tool) or on a tablet in the waiting rooms of clinics. We can foresee two issues in the effective deployment of the app in real-life clinical settings: First, as a job-support tool, it would be ideally used by well-trained FP providers, but the marginal training required to use the app is minimal.Second, the app is not designed to be part of a medical information system: If a clinic or a health system wanted to use it to link client data across FP visits over time and merge it with other relevant data for the client, then it would need to be professionally adapted for those purposes. Last, our findings complement several broader trends. Digital tools are becoming ubiquitous, including for health technology, and it is clear that even in our setting—personal discussions around a sensitive topic—they can be well accepted by both clients and providers alike. We see notable impacts from personalized recommendations, which are in part made feasible exactly due to digitization. The potential social welfare benefits of individual rankings may extend to a wide variety of environments, especially online, going beyond health to education and household finance.