Publication:
Effects of a Lottery Incentive on Sexually Transmitted Infections and HIV Incidence among Female Sex Workers in Tanzania: Results from the RESPECT II Randomized Trial

Loading...
Thumbnail Image
Files in English
English PDF (978.23 KB)
92 downloads
English Text (77.64 KB)
12 downloads
Date
2023-09-26
ISSN
Published
2023-09-26
Author(s)
Balampama, Marianna
Dow, William H.
Hémono, Rebecca
Editor(s)
Abstract
Female sex workers are a key population who experience a disproportionately high burden of HIV and sexually transmitted infections. A growing body of evidence suggests that financial incentives can reduce risky sexual behavior and the incidence of HIV and sexually transmitted infections; however, few studies have examined a lottery-based incentive mechanism or been conducted with female sex workers. This paper examines the effect of a lottery intervention on the combined incidence of HIV and herpes simplex virus 2 among female sex workers in Tanzania. The RESPECT II trial was an unmasked, two-arm, parallel group randomized controlled trial conducted in Dar es Salaam, Tanzania among 2,206 enrollees from 2018 to 2021. Participants were randomized in a one-to-one ratio to the basic test control group or to the lottery intervention group. The basic test group received testing and counseling for HIV and biweekly text messages with information on safe sex practices. The lottery group received the basic test group intervention plus entry into a weekly lottery with a 100,000 Tanzanian shilling (US$50) reward offered to 10 randomly selected participants, conditional on negative test results for syphilis and trichomonas. The primary outcome was combined HIV and herpes simplex virus 2 incidence after 36 months. The results showed no statistically significant effect on this primary outcome. Thus the study finds no evidence that the lottery-based incentives reduced the incidence of HIV and sexually transmitted infections among the female sex worker population. However, the results may have been affected by disruption from the COVID-19 pandemic, and unexpectedly high study attrition levels made it impossible to statistically rule out possible moderate-sized effects.
Link to Data Set
Citation
Balampama, Marianna; de Walque, Damien; Dow, William H.; Hémono, Rebecca. 2023. Effects of a Lottery Incentive on Sexually Transmitted Infections and HIV Incidence among Female Sex Workers in Tanzania: Results from the RESPECT II Randomized Trial. Policy Research Working Paper; 10571. © World Bank. http://hdl.handle.net/10986/40395 License: CC BY 3.0 IGO.
Associated URLs
Associated content
Report Series
Report Series
Other publications in this report series
  • Publication
    Geopolitics and the World Trading System
    (Washington, DC: World Bank, 2024-12-23) Mattoo, Aaditya; Ruta, Michele; Staiger, Robert W.
    Until the beginning of this century, the GATT/WTO system worked. Economic research provided a compelling explanation. It showed that if governments maximize the well-being of their own countries broadly defined, GATT/WTO principles would facilitate mutually beneficial cooperation over their trade policy choices. Now heightened geopolitical rivalry seems to have undermined the WTO. A simple transposition of the previous rationalization suggests that geopolitics and trade cooperation are not compatible. The paper shows that this is only true if rivalry eclipses any consideration of own-country well-being. In all other circumstances, there are gains from trade cooperation even with geopolitics. Furthermore, the WTO’s relevance is in question only if it adheres too rigidly to its existing rules and norms. Through measured adaptation to the geopolitical imperative, the WTO can continue to thrive as a forum for multilateral trade cooperation in the age of geopolitics.
  • Publication
    Tradeoffs over Rate Cycles
    (Washington, DC: World Bank, 2025-05-23) Forbes, Kristin; Ha, Jongrim; Kose, M. Ayhan
    Central banks often face tradeoffs in how their monetary policy decisions impact economic activity (including employment), inflation and the price level. This paper assesses how these tradeoffs have evolved over time and varied across countries, with a focus on understanding the post-pandemic adjustment. To make these comparisons, we compile a cross-country, historical database of “rate cycles” (i.e., easing and tightening phases for monetary policy) for 24 advanced economies from 1970 through 2024. This allows us to quantify the characteristics of interest rate adjustments and corresponding macroeconomic outcomes and tradeoffs. We also calculate Sacrifice Ratios (output losses per inflation reduction) and document a historically low “sacrifice” during the post-pandemic tightening. This popular measure, however, ignores adjustments in the price level—which increased by more after the pandemic than over the past four decades. A series of regressions and simulations suggest monetary policy (and particularly the timing and aggressiveness of rate hikes) play a meaningful role in explaining these tradeoffs and how adjustments occur during tightening phases. Central bank credibility is the one measure we assess that corresponds to only positive outcomes and no difficult tradeoffs.
  • Publication
    Global Socio-economic Resilience to Natural Disasters
    (Washington, DC: World Bank, 2025-05-22) Middelanis, Robin; Jafino, Bramka Arga; Hill, Ruth; Nguyen, Minh Cong; Hallegatte, Stephane
    Most disaster risk assessments use damages to physical assets as their central metric, often neglecting distributional impacts and the coping and recovery capacity of affected people. To address this shortcoming, the concepts of well-being losses and socio-economic resilience—the ability to experience asset losses without a decline in well-being—have been proposed. This paper uses microsimulations to produce a global estimate of well-being losses from, and socio-economic resilience to, natural disasters, covering 132 countries. On average, each $1 in disaster-related asset losses results in well-being losses equivalent to a $2 uniform national drop in consumption, with significant variation within and across countries. The poorest income quintile within each country incurs only 9% of national asset losses but accounts for 33% of well-being losses. Compared to high-income countries, low-income countries experience 67% greater well-being losses per dollar of asset losses and require 56% more time to recover. Socio-economic resilience is uncorrelated with exposure or vulnerability to natural hazards. However, a 10 percent increase in GDP per capita is associated with a 0.9 percentage point gain in resilience, but this benefit arises indirectly—such as through higher rate of formal employment, better financial inclusion, and broader social protection coverage—rather than from higher income itself. This paper assess ten policy options and finds that socio-economic and financial interventions (such as insurance and social protection) can effectively complement asset-focused measures (e.g., construction standards) and that interventions targeting low-income populations usually have higher returns in terms of avoided well-being losses per dollar invested.
  • Publication
    From Chalkboards to Chatbots
    (Washington, DC: World Bank, 2025-05-20) De Simone, Martin; Tiberti, Federico; Barron Rodriguez, Maria; Manolio, Federico; Mosuro, Wuraola; Dikoru, Eliot Jolomi
    This study evaluates the impact of a program leveraging large language models for virtual tutoring in secondary education in Nigeria. Using a randomized controlled trial, the program deployed Microsoft Copilot (powered by GPT-4) to support first-year senior secondary students in English language learning over six weeks. The intervention demonstrated a significant improvement of 0.31 standard deviation on an assessment that included English topics aligned with the Nigerian curriculum, knowledge of artificial intelligence and digital skills. The effect on English, the main outcome of interest, was of 0.23 standard deviations. Cost-effectiveness analysis revealed substantial learning gains, equating to 1.5 to 2 years of ’business-as-usual’ schooling, situating the intervention among some of the most cost-effective programs to improve learning outcomes. An analysis of heterogeneous effects shows that while the program benefits students across the baseline ability distribution, the largest effects are for female students, and those with higher initial academic performance. The findings highlight that artificial intelligence-powered tutoring, when designed and used properly, can have transformative impacts in the education sector in low-resource settings.
  • Publication
    Disentangling the Key Economic Channels through Which Infrastructure Affects Jobs
    (Washington, DC: World Bank, 2025-04-03) Vagliasindi, Maria; Gorgulu, Nisan
    This paper takes stock of the literature on infrastructure and jobs published since the early 2000s, using a conceptual framework to identify the key channels through which different types of infrastructure impact jobs. Where relevant, it highlights the different approaches and findings in the cases of energy, digital, and transport infrastructure. Overall, the literature review provides strong evidence of infrastructure’s positive impact on employment, particularly for women. In the case of electricity, this impact arises from freeing time that would otherwise be spent on household tasks. Similarly, digital infrastructure, particularly mobile phone coverage, has demonstrated positive labor market effects, often driven by private sector investments rather than large public expenditures, which are typically required for other large-scale infrastructure projects. The evidence on structural transformation is also positive, with some notable exceptions, such as studies that find no significant impact on structural transformation in rural India in the cases of electricity and roads. Even with better market connections, remote areas may continue to lack economic opportunities, due to the absence of agglomeration economies and complementary inputs such as human capital. Accordingly, reducing transport costs alone may not be sufficient to drive economic transformation in rural areas. The spatial dimension of transformation is particularly relevant for transport, both internationally—by enhancing trade integration—and within countries, where economic development tends to drive firms and jobs toward urban centers, benefitting from economies scale and network effects. Turning to organizational transformation, evidence on skill bias in developing countries is more mixed than in developed countries and may vary considerably by context. Further research, especially on the possible reasons explaining the differences between developed and developing economies, is needed.
Journal
Journal Volume
Journal Issue

Related items

Showing items related by metadata.

  • Publication
    Effect of a Lottery Intervention on Gender-Based Violence among Female Sex Workers in Dar es Salaam, Tanzania
    (World Bank, 2023-10-02) Hémono, Rebecca; Balampama, Marianna; de Walque, Damien; McCoy, Sandra I.; Dow, William H.
    Financial incentives are a promising approach for HIV prevention. Some studies have shown that financial incentive interventions aimed to promote positive health and social behaviors have mixed or harmful effects on gender-based violence, and little is known about their effects among higher risk groups such as female sex workers. To address this gap, this study investigated the relationship between a lottery-based incentive and gender-based violence among female sex workers in Dar es Salaam, Tanzania. Data were analyzed from the RESPECT II trial, which enrolled 2,206 female sex workers in Dar es Salaam, Tanzania, to evaluate the effect of a lottery-based incentive on HIV and sexually transmitted infections. Participants were randomized in a one-to-one ratio to: (1) the basic test group (control), which provided baseline testing and counseling for HIV and sexually transmitted infections and bi-weekly text messages on safe sex practices; or (2) the lottery group, which included the basic test group intervention plus entry into a weekly random lottery for an award of 100,000 Tanzanian shillings conditional on negative tests for sexually transmitted infections (syphilis and trichomonas vaginalis). An intent-to-treat analysis was conducted to estimate differences in physical and sexual gender-based violence (overall), and intimate partner violence and non-partner violence between treatment arms at endline, with estimates expressed as unadjusted prevalence differences with 95 percent confidence intervals. Adjusted estimates controlled for baseline reports of violence. Multiple imputation and inverse-probability of treatment weighting were used to account for missing data. Causal, population-level impacts were estimated using g-computation. Gender-based violence, intimate partner violence, and non-partner violence declined in both treatment arms over the study period among the sample of 1,117 female sex workers retained at endline. The lottery group had a lower prevalence of gender-based violence overall, intimate partner violence, and non-partner violence compared to control at endline; however, the differences were not statistically significant. The results indicate that the lottery intervention had no effect on violence outcomes among endline participants in the RESPECT II trial. These results suggest that this economic approach does not pose additional risks of violence in the context of sex work; however, they must be interpreted with caution due to high attrition in the study sample. Additional research is warranted to examine how this incentive mechanism impacts violence for female sex workers.
  • Publication
    Influence of COVID-19 on Female Sex Workers in Dar es Salaam, Tanzania
    (World Bank, Washington, DC, 2023-10-02) Balampama, Marianna; De Walque, Damien; Dow, William H.; Hémono, Rebbeca
    This study investigates how the landscape of sex work in Dar es Salaam, Tanzania, evolved in the context of the COVID-19 epidemic. Using a mixed-methods approach, the analysis triangulates data from quantitative and qualitative sources to quantify shifts in income, demand, and client frequency and describe female sex workers’ perspectives on their work environment. The COVID-19 restrictions introduced in early 2020 resulted in dramatic decreases in sex work income, leading to extreme financial vulnerability, food insecurity, and challenges in meeting other basic needs such as paying rent. However, in a 2021 follow-up survey, sex workers reported the summer of 2021 as a key turning point, with the demand for sex work rebounding to closer to pre-pandemic levels. Notably, despite the average number of unique weekly clients not yet having fully rebounded, by 2021 the price per client and the total monthly sex work income had returned to pre-pandemic levels. This may potentially be explained by an increased number of repeat clients, which represented a larger proportion of all clients during the COVID-19 pandemic.
  • Publication
    Female Sex Workers Use Power Over Their Day-to-Day Lives to Meet the Condition of a Conditional Cash Transfer Intervention to Incentivize Safe Sex
    (Elsevier, 2017-05) Cooper, Jan E.; Dow, William H.; de Walque, Damien; Keller, Ann C.; McCoy, Sandra I.; Fernald, Lia C.H.; Balampama, Marianna P.; Kalolella, Admirabilis; Packel, Laura J.; Wechsberg, Wendee M.; Ozer, Emily J.
    Female Sex Workers are a core population in the HIV epidemic, and interventions such as conditional cash transfers (CCTs), effective in other health domains, are a promising new approach to reduce the spread of HIV. Here we investigate how a population of Tanzanian female sex workers, though constrained in many ways, experience and use their power in the context of a CCT intervention that incentivizes safe sex. We analyzed 20 qualitative in-depth interviews with female sex workers enrolled in a randomized-controlled CCT program, the RESPECT II pilot, and found that while such women have limited choices, they do have substantial power over their work logistics that they leveraged to meet the conditions of the CCT and receive the cash award. It was through these decisions over work logistics, such as reducing the number of workdays and clients, that the CCT intervention had its greatest impact on modifying female sex workers’ behavior.
  • Publication
    Incentivising Safe Sex : A Randomised Trial of Conditional Cash Transfers for HIV and Sexually Transmitted Infection Prevention in Rural Tanzania
    (2012-02-08) Dow, William H.; de Walque, Damien; Nathan, Rose; Abdul, Ramadhani; Abilahi, Faraji; Gong, Erick; Isdahl, Zachary; Jamison, Julian; Jullu, Boniphace; Krishnan, Suneeta; Majura, Albert; Migue, Edward; Moncada, Jeanne; Mtenga, Sally; Mwanyangala, Mathew Alexander; Packel, Laura; Schachter, Julius; Shirima, Kizito; Medlin, Carol A.
    Objective The authors evaluated the use of conditional cash transfers as an HIV and sexually transmitted infection prevention strategy to incentivise safe sex. Design An unblinded, individually randomised and controlled trial. Setting 10 villages within the Kilombero/Ulanga districts of the Ifakara Health and Demographic Surveillance System in rural south-west Tanzania. Participants The authors enrolled 2399 participants, aged 18–30 years, including adult spouses. Interventions Participants were randomly assigned to either a control arm (n=1124) or one of two intervention arms: low-value conditional cash transfer (eligible for $10 per testing round, n=660) and high-value conditional cash transfer (eligible for $20 per testing round, n=615). The authors tested participants every 4 months over a 12-month period for the presence of common sexually transmitted infections. In the intervention arms, conditional cash transfer payments were tied to negative sexually transmitted infection test results. Anyone testing positive for a sexually transmitted infection was offered free treatment, and all received counselling. Main outcome measures The primary study end point was combined prevalence of the four sexually transmitted infections, which were tested and reported to subjects every 4 months: Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis and Mycoplasma genitalium. The authors also tested for HIV, herpes simplex virus 2 and syphilis at baseline and month 12. Results At the end of the 12-month period, for the combined prevalence of any of the four sexually transmitted infections, which were tested and reported every 4 months (C trachomatis, N gonorrhoeae, T vaginalis and M genitalium), unadjusted RR for the high-value conditional cash transfer arm compared to controls was 0.80 (95% CI 0.54 to 1.06) and the adjusted RR was 0.73 (95% CI 0.47 to 0.99). Unadjusted RR for the high-value conditional cash transfer arm compared to the low-value conditional cash transfer arm was 0.76 (95% CI 0.49 to 1.03) and the adjusted RR was 0.69 (95% CI 0.45 to 0.92). No harm was reported. Conclusions Conditional cash transfers used to incentivise safer sexual practices are a potentially promising new tool in HIV and sexually transmitted infections prevention. Additional larger study would be useful to clarify the effect size, to calibrate the size of the incentive and to determine whether the intervention can be delivered cost effectively. Trial registration number NCT00922038 ClinicalTrials.gov.
  • Publication
    Potential Applications of Conditional Cash Transfers for Prevention of Sexually Transmitted Infections and HIV in Sub-Saharan Africa
    (World Bank, Washington, DC, 2008-07) Medlin, Carol; de Walque, Damien
    A growing number of developing countries have introduced conditional cash transfer programs that provide money to poor families with certain contingencies attached - such as requiring school attendance or regular immunization and health check-ups. As the popularity of conditional cash transfer programs has grown, experimentation with potential applications in other areas of health, such as sexual and reproductive health, and HIV prevention, in particular, has also increased. Evaluations of conditional cash transfer programs have focused almost exclusively on uptake of health and educational services, which make relatively low demands of participants compared with more complex interventions, which require the cessation of risky behaviors, such as smoking, obesity, and substance abuse. The literature on contingency management - based on the principle that behavioral change occurs when appropriate behaviors are reinforced and rewarded - provides a richer picture of the complexity of the use of conditionality to encourage healthy behavioral change. This paper examines developing countries' experiences with conditional cash transfer programs and the results of trials in clinical settings on the efficacy of contingency management, and addresses their relevance for designing conditional cash transfer programs to address risky sexual behavior and promote the prevention of sexually transmitted infections and HIV in Sub-Saharan Africa.

Users also downloaded

Showing related downloaded files

  • Publication
    Economic Recovery
    (World Bank, Washington, DC, 2021-04-06) Malpass, David; Georgieva, Kristalina; Yellen, Janet
    World Bank Group President David Malpass spoke about the world facing major challenges, including COVID, climate change, rising poverty and inequality and growing fragility and violence in many countries. He highlighted vaccines, working closely with Gavi, WHO, and UNICEF, the World Bank has conducted over one hundred capacity assessments, many even more before vaccines were available. The World Bank Group worked to achieve a debt service suspension initiative and increased transparency in debt contracts at developing countries. The World Bank Group is finalizing a new climate change action plan, which includes a big step up in financing, building on their record climate financing over the past two years. He noted big challenges to bring all together to achieve GRID: green, resilient, and inclusive development. Janet Yellen, U.S. Secretary of the Treasury, mentioned focusing on vulnerable people during the pandemic. Kristalina Georgieva, Managing Director of the International Monetary Fund, focused on giving everyone a fair shot during a sustainable recovery. All three commented on the importance of tackling climate change.
  • Publication
    South Asia Development Update, April 2024: Jobs for Resilience
    (Washington, DC: World Bank, 2024-04-02) World Bank
    South Asia is expected to continue to be the fastest-growing emerging market and developing economy (EMDE) region over the next two years. This is largely thanks to robust growth in India, but growth is also expected to pick up in most other South Asian economies. However, growth in the near-term is more reliant on the public sector than elsewhere, whereas private investment, in particular, continues to be weak. Efforts to rein in elevated debt, borrowing costs, and fiscal deficits may eventually weigh on growth and limit governments' ability to respond to increasingly frequent climate shocks. Yet, the provision of public goods is among the most effective strategies for climate adaptation. This is especially the case for households and farms, which tend to rely on shifting their efforts to non-agricultural jobs. These strategies are less effective forms of climate adaptation, in part because opportunities to move out of agriculture are limited by the region’s below-average employment ratios in the non-agricultural sector and for women. Because employment growth is falling short of working-age population growth, the region fails to fully capitalize on its demographic dividend. Vibrant, competitive firms are key to unlocking the demographic dividend, robust private investment, and workers’ ability to move out of agriculture. A range of policies could spur firm growth, including improved business climates and institutions, the removal of financial sector restrictions, and greater openness to trade and capital flows.
  • Publication
    Media and Messages for Nutrition and Health
    (World Bank, Washington, DC, 2020-06) Calleja, Ramon V., Jr.; Mbuya, Nkosinathi V.N.; Morimoto, Tomo; Thitsy, Sophavanh
    The Lao People’s Democratic Republic (Lao PDR) has experienced rapid and significant economic growth over the past decade. However, poor nutritional outcomes remain a concern. Rates of childhood undernutrition are particularly high in remote, rural, and upland areas. Media have the potential to play an important role in shaping health and nutrition–related behaviors and practices as well as in promoting sociocultural and economic development that might contribute to improved nutritional outcomes. This report presents the results of a media audit (MA) that was conducted to inform the development and production of mass media advocacy and communication strategies and materials with a focus on maternal and child health and nutrition that would reach the most people from the poorest communities in northern Lao PDR. Making more people aware of useful information, essential services and products and influencing them to use these effectively is the ultimate goal of mass media campaigns, and the MA measures the potential effectiveness of media efforts to reach this goal. The effectiveness of communication channels to deliver health and nutrition messages to target beneficiaries to ensure maximum reach and uptake can be viewed in terms of preferences, satisfaction, and trust. Overall, the four most accessed media channels for receiving information among communities in the study areas were village announcements, mobile phones, television, and out-of-home (OOH) media. Of the accessed media channels, the top three most preferred channels were village announcements (40 percent), television (26 percent), and mobile phones (19 percent). In terms of trust, village announcements were the most trusted source of information (64 percent), followed by mobile phones (14 percent) and television (11 percent). Hence of all the media channels, village announcements are the most preferred, have the most satisfied users, and are the most trusted source of information in study communities from four provinces in Lao PDR with some of the highest burden of childhood undernutrition.
  • Publication
    Remarks at the United Nations Biodiversity Conference
    (World Bank, Washington, DC, 2021-10-12) Malpass, David
    World Bank Group President David Malpass discussed biodiversity and climate change being closely interlinked, with terrestrial and marine ecosystems serving as critically important carbon sinks. At the same time climate change acts as a direct driver of biodiversity and ecosystem services loss. The World Bank has financed biodiversity conservation around the world, including over 116 million hectares of Marine and Coastal Protected Areas, 10 million hectares of Terrestrial Protected Areas, and over 300 protected habitats, biological buffer zones and reserves. The COVID pandemic, biodiversity loss, climate change are all reminders of how connected we are. The recovery from this pandemic is an opportunity to put in place more effective policies, institutions, and resources to address biodiversity loss.
  • Publication
    Education, Social Norms, and the Marriage Penalty
    (Washington, DC: World Bank, 2024-10-16) Bussolo, Maurizio; Rexer, Jonah; Triyana, Margaret
    A growing literature attributes gender inequality in labor market outcomes in part to the reduction in female labor supply after childbirth, the child penalty. However, if social norms constrain married women’s activities outside the home, then marriage can independently reduce employment, even in the absence childbearing. Given the correlation in timing between childbirth and marriage, conventional estimates of child penalties will conflate these two effects. The paper studies the marriage penalty in South Asia, a context featuring conservative gender norms and low female labor force participation. The study introduces a split-sample, pseudo-panel approach that allows for the separation of marriage and child penalties even in the absence of individual-level panel data. Marriage reduces women’s labor force participation in South Asia by 12 percentage points, whereas the marginal penalty of childbearing is small. Consistent with the central roles of both opportunity costs and social norms, the marriage penalty is smaller among cohorts with higher education and less conservative gender attitudes.