Publication: Effect of a Lottery Intervention on Gender-Based Violence among Female Sex Workers in Dar es Salaam, Tanzania: Results from a Randomized Trial
Loading...
Date
2023-10-02
ISSN
Published
2023-10-02
Author(s)
Editor(s)
Abstract
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.
Link to Data Set
Citation
“Hémono, Rebecca; Balampama, Marianna; de Walque, Damien; McCoy, Sandra I.; Dow, William H.. 2023. Effect of a Lottery Intervention on Gender-Based Violence among Female Sex Workers in Dar es Salaam, Tanzania: Results from a Randomized Trial. Policy Research Working Paper; 10573. © World Bank. http://hdl.handle.net/10986/40417 License: CC BY 3.0 IGO.”
Associated URLs
Associated content
Other publications in this report series
Publication The Macroeconomic Implications of Climate Change Impacts and Adaptation Options(Washington, DC: World Bank, 2025-05-29)Estimating the macroeconomic implications of climate change impacts and adaptation options is a topic of intense research. This paper presents a framework in the World Bank's macrostructural model to assess climate-related damages. This approach has been used in many Country Climate and Development Reports, a World Bank diagnostic that identifies priorities to ensure continued development in spite of climate change and climate policy objectives. The methodology captures a set of impact channels through which climate change affects the economy by (1) connecting a set of biophysical models to the macroeconomic model and (2) exploring a set of development and climate scenarios. The paper summarizes the results for five countries, highlighting the sources and magnitudes of their vulnerability --- with estimated gross domestic product losses in 2050 exceeding 10 percent of gross domestic product in some countries and scenarios, although only a small set of impact channels is included. The paper also presents estimates of the macroeconomic gains from sector-level adaptation interventions, considering their upfront costs and avoided climate impacts and finding significant net gross domestic product gains from adaptation opportunities identified in the Country Climate and Development Reports. Finally, the paper discusses the limits of current modeling approaches, and their complementarity with empirical approaches based on historical data series. The integrated modeling approach proposed in this paper can inform policymakers as they make proactive decisions on climate change adaptation and resilience.Publication From Patriarchy to Policy(Washington, DC: World Bank, 2025-05-29)Legal institutions play an important role in shaping gender equality in economic domains, from inheritance to labor markets. But where do gender equal laws come from? Using cross-country data on social norms and legal equality, this paper investigates the socio-cultural roots of gender inequity in the legal system and its implications for female labor force participation. To identify the impact of social norms, the analysis uses an empirical strategy that exploits pre-modern differences in ancestral patriarchal culture as an instrument for present-day gender norms. The findings show that ancestral patriarchal culture is a strong predictor of contemporary norms, and conservative social norms are associated with more gender inequality in the de jure legal framework, the de facto implementation of laws, and the labor market. The paper presents evidence for a political selection mechanism linking norms to laws: countries with more conservative norms elect political leaders who are more hostile to gender equality, who then pass less progressive legislation. The results highlight the cultural roots and political drivers of legalized gender inequality.Publication Geopolitics and the World Trading System(Washington, DC: World Bank, 2024-12-23)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 Rethinking Fiscal Policies(Washington, DC: World Bank, 2025-05-27)This paper examines the redistributive impact of fiscal policy—specifically taxes and transfers—on poverty and inequality in eight countries in the Middle East and North Africa: the Arab Republic of Egypt, Djibouti, the Islamic Republic of Iran, Iraq, Jordan, Morocco, Tunisia, and the West Bank and Gaza. Utilizing the Commitment to Equity framework, the analysis evaluates how fiscal interventions alter income distribution across these diverse national contexts. The results indicate that direct cash transfers and social assistance programs are generally effective in reducing poverty and shielding vulnerable populations, while in-kind benefits—particularly in education and healthcare—significantly contribute to mitigating income inequality. In contrast, generalized subsidies, especially in the energy sector, are fiscally burdensome and largely regressive, offering limited equity gains. Indirect taxes, although important for revenue generation, often exacerbate income disparities. The study underscores the need for comprehensive fiscal reforms, including the expansion of well-targeted transfers, adoption of progressive taxation, and reallocation of inefficient subsidies toward investments in human capital. Successful initiatives, such as Egypt’s Takaful and Karama and Jordan’s Takaful and bread subsidy compensation programs, illustrate scalable models of effective redistribution. Moreover, the Islamic Republic of Iran’s progressive tax policies highlight viable pathways to equitable revenue mobilization. Strengthening investment in education and health is essential for promoting long-term equity, enhancing upward mobility, and supporting inclusive and sustainable development across the region.Publication Yield Gains from Balancing Fertilizer Use(Washington, DC: World Bank, 2025-05-29)As with most agricultural inputs, the optimal use of fertilizer leverages the production complementarities between different types of nutrients. Wide variation in the intensity of nutrient application rates suggests there are potentially large productivity gains to be had from rebalancing fertilizer use across nutrient types even under a fixed expenditure budget. Using detailed information on a large sample of rice fields across three states in eastern India, this paper investigates whether a more balanced use of fertilizer—measured as the ratio of potash to nitrogen applied to a field—can lead to higher yields and revenues. To address the endogeneity of fertilizer application decisions, the analysis exploits the fact that nitrogen-based fertilizers demanded by Indian farmers are mostly produced domestically in a limited number of manufacturing plants, while all potash-based fertilizers must be imported by ship from abroad. Instrumenting for the ratio of potassium-to-nitrogen fertilizer applied on a field with the relative travel distances between farmers’ villages and both the nearest urea production plant and the nearest international port, the paper estimates the impact of more balanced fertilizer use on yields and revenues. The estimates show that at median levels of fertilizer use, and keeping the level of expenditure on fertilizers constant, rebalancing fertilizer application choices such that the potassium-to-nitrogen ratio of fertilizer is doubled would lead to a 4.8 percent increase in yield.
Journal
Journal Volume
Journal Issue
Collections
Related items
Showing items related by metadata.
Publication Effects of a Lottery Incentive on Sexually Transmitted Infections and HIV Incidence among Female Sex Workers in Tanzania(World Bank, Washington, DC, 2023-09-26)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.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)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 Influence of COVID-19 on Female Sex Workers in Dar es Salaam, Tanzania(World Bank, Washington, DC, 2023-10-02)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 Addressing Gender-Based Violence in the Latin American and Caribbean Region : A Critical Review of Interventions(World Bank, Washington, D.C., 2004-10)The authors present an overview of gender-based violence (GBV) in Latin America, with special emphasis on good practice interventions to prevent GBV or offer services to its survivors or perpetrators. Intimate partner violence and sexual coercion are the most common forms of GBV, and these are the types of GBV that they analyze. GBV has serious consequences for women's health and well-being, ranging from fatal outcomes, such as homicide, suicide, and AIDS-related deaths, to nonfatal outcomes, such as physical injuries, chronic pain syndrome, gastrointestinal disorders, complications during pregnancy, miscarriage, and low birth-weight of children. GBV also poses significant costs for the economies of developing countries, including lower worker productivity and incomes, and lower rates of accumulation of human and social capital. The authors examine good practice approaches in justice, health, education, and multisectoral approaches. In each sector, they identify good practices for: (1) law and policies; (2) institutional reforms; (3) community-level interventions; and (4) individual behavior change strategies.Publication Gender-Based Violence Country Profile(Washington, DC, 2023-06-01)St. Vincent and the Grenadines comprises a main island, Saint Vincent, and thirty-two other islands, islets, and cays in the archipelago of the Grenadines (SVG). It is a unicameral democracy, with fifteen seats for elected members in the House of Representatives. Historically, much of the economic activity was concentrated on agriculture, particularly banana cultivation and export to the United Kingdom (UK) and Europe. In April 2021, the explosive eruption of the La Soufrière volcano in the north of Saint Vincent destroyed much of Saint Vincent’s most productive agricultural lands. This affected negatively SVG as unlike most of its tourism-dependent neighbors, the Vincentian economy is primarily agricultural.
Users also downloaded
Showing related downloaded files
Publication Remarks to the Annual Meetings 2020 Development Committee(World Bank, Washington, DC, 2020-10-16)David Malpass, President of the World Bank Group, announced that the Board approved a fast track approach to emergency health support programs that now covers 111 countries. Most projects are well advanced, with average disbursement upward of 40 percent. The goal is to take broad, fast action early. The operational framework presented back in June has positioned the Bank to help countries address immediate health threats and social and economic impacts and maintain our focus on long-term development. The Bank is making good progress toward the 15-month target of 160 billion dollars in surge financing. Much of it is for the poorest countries and will take the form of grants or low-rate, long-maturity loans. IFC, through the Global Health Platform, will be providing financing to vaccine manufacturers to foster expanded production of COVID-19 vaccines in both part 1 and 2 countries, providing production is reserved for emerging markets. The Development Committee holds a unique place in the international architecture. It is the only global forum in which the Governments of developed countries and the Governments of developing countries, creditor countries and borrower countries, come together to discuss development and the ‘net transfer of resources to developing countries.’ The current International Financial Architecture system is skewed in favor of the rich and creditor countries. It is important that all voices are heard, so Malpass urged the Ministers of developing countries to use their voice and speak their minds today. Malpass urged consideration of how we can build a new approach to debt restructuring that allows for a fair relationship and balance between creditors and debtors. This will be critical in restoring growth in developing countries; and helping reverse the inequality.Publication Doing Business 2014 : Understanding Regulations for Small and Medium-Size Enterprises(Washington, DC: World Bank Group, 2013-10-28)Eleventh in a series of annual reports comparing business regulation in 185 economies, Doing Business 2014 measures regulations affecting 11 areas of everyday business activity: Starting a business, Dealing with construction permits, Getting electricity, Registering property, Getting credit, Protecting investors, Paying taxes, Trading across borders, Enforcing contracts, Closing a business, Employing workers. The report updates all indicators as of June 1, 2013, ranks economies on their overall “ease of doing business”, and analyzes reforms to business regulation – identifying which economies are strengthening their business environment the most. The Doing Business reports illustrate how reforms in business regulations are being used to analyze economic outcomes for domestic entrepreneurs and for the wider economy. Doing Business is a flagship product by the World Bank and IFC that garners worldwide attention on regulatory barriers to entrepreneurship. More than 60 economies use the Doing Business indicators to shape reform agendas and monitor improvements on the ground. In addition, the Doing Business data has generated over 870 articles in peer-reviewed academic journals since its inception.Publication World Development Report 2006(Washington, DC, 2005)This year’s Word Development Report (WDR), the twenty-eighth, looks at the role of equity in the development process. It defines equity in terms of two basic principles. The first is equal opportunities: that a person’s chances in life should be determined by his or her talents and efforts, rather than by pre-determined circumstances such as race, gender, social or family background. The second principle is the avoidance of extreme deprivation in outcomes, particularly in health, education and consumption levels. This principle thus includes the objective of poverty reduction. The report’s main message is that, in the long run, the pursuit of equity and the pursuit of economic prosperity are complementary. In addition to detailed chapters exploring these and related issues, the Report contains selected data from the World Development Indicators 2005‹an appendix of economic and social data for over 200 countries. This Report offers practical insights for policymakers, executives, scholars, and all those with an interest in economic development.Publication Classroom Assessment to Support Foundational Literacy(Washington, DC: World Bank, 2025-03-21)This document focuses primarily on how classroom assessment activities can measure students’ literacy skills as they progress along a learning trajectory towards reading fluently and with comprehension by the end of primary school grades. The document addresses considerations regarding the design and implementation of early grade reading classroom assessment, provides examples of assessment activities from a variety of countries and contexts, and discusses the importance of incorporating classroom assessment practices into teacher training and professional development opportunities for teachers. The structure of the document is as follows. The first section presents definitions and addresses basic questions on classroom assessment. Section 2 covers the intersection between assessment and early grade reading by discussing how learning assessment can measure early grade reading skills following the reading learning trajectory. Section 3 compares some of the most common early grade literacy assessment tools with respect to the early grade reading skills and developmental phases. Section 4 of the document addresses teacher training considerations in developing, scoring, and using early grade reading assessment. Additional issues in assessing reading skills in the classroom and using assessment results to improve teaching and learning are reviewed in section 5. Throughout the document, country cases are presented to demonstrate how assessment activities can be implemented in the classroom in different contexts.Publication World Development Report 2011(World Bank, 2011)The 2011 World development report looks across disciplines and experiences drawn from around the world to offer some ideas and practical recommendations on how to move beyond conflict and fragility and secure development. The key messages are important for all countries-low, middle, and high income-as well as for regional and global institutions: first, institutional legitimacy is the key to stability. When state institutions do not adequately protect citizens, guard against corruption, or provide access to justice; when markets do not provide job opportunities; or when communities have lost social cohesion-the likelihood of violent conflict increases. Second, investing in citizen security, justice, and jobs is essential to reducing violence. But there are major structural gaps in our collective capabilities to support these areas. Third, confronting this challenge effectively means that institutions need to change. International agencies and partners from other countries must adapt procedures so they can respond with agility and speed, a longer-term perspective, and greater staying power. Fourth, need to adopt a layered approach. Some problems can be addressed at the country level, but others need to be addressed at a regional level, such as developing markets that integrate insecure areas and pooling resources for building capacity Fifth, in adopting these approaches, need to be aware that the global landscape is changing. Regional institutions and middle income countries are playing a larger role. This means should pay more attention to south-south and south-north exchanges, and to the recent transition experiences of middle income countries.