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date: 22 July 2019

Economic Incentives, Risk Behaviors, and HIV

Summary and Keywords

Conditional economic incentives are a theoretically grounded approach for eliciting behavior change. The rationale stems from present-biased preferences, by which individuals attach greater value to benefits in the present and heavily discount long-term health. A growing literature documents the use of economic incentives in the HIV field. Small and frequent conditional economic incentives offered to vulnerable populations can contribute to behavior change. Economic incentives accompanied with other strategies can help overcome obstacles to access health services and in general seem to improve linkage to HIV care, prevention interventions, and adherence to HIV treatment. Future identification of promising combinations of intervention components, modalities, and strategies may yield maximum impact.

Keywords: health economics, behavioral economics, HIV acquisition, risk behavior, sexually transmitted diseases, non-rational behaviors, prospect theory, economic incentives

Incentives for Behavior Change

Humans often engage in behaviors that have negative consequences for their own health. Ignorance of consequences rarely explains such paradoxical behavior. Even with access to good information and education about the consequences of harmful habits, many individuals continue to choose unhealthy options and activities. Furthermore, even when evidence-based interventions do have an impact on changing risk behaviors, the effects frequently are temporary and disappear soon after the intervention stops. Contrary to traditional economic theory, with which rational individuals make decisions using appropriately all the information available, simple observation—and perhaps introspection—suggests that individuals make decisions based on imperfect information and that humans are prone to be affected by various psychological forces.

Based on the long list of psychological theory–based deviations of the traditional economic model of individual decision making, researchers and policymakers have designed various mechanisms to change health-related behaviors. The content of the interventions ranges from simple interventions to guide people to make healthier choices to more complex interventions that seek behavior modification through lifestyle changes and noxious behavior reduction (smoking, binge drinking and eating, unsafe sex, etc.). In terms of HIV prevention and treatment, traditional approaches and mass media have been only modestly effective in effecting and sustaining behavior change (Dick, Ferguson, & Ross, 2006; Rotheram-Borus, 2000, Kerrigan et al., 2006). One mechanism widely implemented to promote health behavior change is the use of financial incentives (Kane, Johnson, Town, & Butler, 2004; Hall, 2011). One example is price adjustment and taxation of unhealthy products (e.g., tobacco, alcohol, sugar-sweetened drinks), which has been proven to reduce the consumption of these products (Chaloupka, Yurekli, & Fong, 2012; Wagenaar, Salois, & Komro, 2009). On the other hand, there are also explicit economic incentives in the form of financial rewards that seek to change health-related behaviors. In this specific context, economic incentives have proven effective for attaining health-related targets such as smoking cessation, weight loss, increased physical activity (Strohacker et al., 2014, Halpern et al., 2015, Sykes-Muskett et al., 2015) being free of sexually transmitted diseases as well as economic penalties for failing to adhere to healthy behavior (De Walque et al., 2012).

A large body of literature in psychology and behavioral economics supports the notion that people can be nudged with small incentives to improve their own health. Conditional economic incentives are a theoretically grounded approach for eliciting behavior change. They are meant to counteract present-biased preferences, by which individuals attach greater value to the benefits of the present, even if the long-term benefits to health may exceed immediate benefits. That is, financial incentives can help individuals feel they can reduce the immediate gratification of unhealthy or risky behaviors, including the pleasure of alcohol consumption, cigarette smoking, unsafe sex, etc. Economic theory thus suggests that financial incentives can effectively increase the present value of healthy behaviors. Although there are studies suggesting the effectiveness of financial incentives on changing behaviors in the short term, the evidence is inconclusive with respect to their long-term effects. The evidence has proved that the sustainability of behavior change in areas such as tobacco smoking (Cahill & Perera, 2011), physical activity (Mitchell et al., 2013), and weight lost (Paul-Ebhohimhen & Avenell, 2008, John et al., 2011), and safe sexual practices (Galárraga et al., 2017) may represent a challenge once the economic incentives are removed. By contrast, more robust effects of the incentives have been found on uptake of medical visits, attendance to medical appointments, and adherence to treatment (Kane et al., 2004, Sutherland et al., 2008).

The use of conditional cash incentives to improve the effectiveness of interventions for the prevention of sexually transmitted infections is relatively new. Most of the incentives used in the HIV field have been experimentally evaluated in generalized epidemic settings, finding that small economic incentives can dramatically improve the return rates for HIV testing (Thornton, 2008). Unlike other areas of research, meta analyses and earlier reviews have shown that economic incentives have been effective in improving healthcare utilization and adherence to treatment, particularly in low-income and young populations (Peersman & Levy, 1998). However, there is still lack of evidence with respect to the effectiveness of economic incentives for HIV prevention and treatment adherence, particularly among groups of adult populations with different vulnerability profiles. Moreover, there is little evidence regarding the scope of the impact of economic incentives to improve not only healthcare utilization and health services adherence but also to change risky sexual behaviors.

This article summarizes a growing list of recent works that document the use of economic incentives in the HIV field. First, it contrasts conventional economic theory with the behavioral economics view. Second, it documents interventions to overcome behavioral biases. Third, it provides an overview of the evidence of interventions and tools that support healthy behaviors. Fourth, it provides a more in-depth review of economic incentives to improve HIV prevention and treatment outcomes and their sustainability over time.

Synergy Between Psychology and Economics

According to standard economic theory, individuals make choices to maximize their utility using the information available and processing this information optimally. In this context, preferences are consistently time discounted by their own payoffs and independent from the framing of the decision (DellaVigna, 2009). However, laboratory and field experiments show deviations from the standard theory in each step of the decision-making process: (1) non-standard preferences, (2) incorrect beliefs, and (3) systematic biases in decision making (DellaVigna, 2009). First, non-standard preferences focus on three specific dimensions: time, risk, and social prefernces. In the standard model, discount rates are independent of the period in which utility is evaluated; the assumption is that future preferences do not change at different points in time. However, in different experiments evaluating decisions, these preferences tend to be different when outcomes in the nearer versus the more distant future are compared. Discounting is steeper as the outcome gets closer, which refers to the time inconsistency of preferences (Phelps & Pollak, 2006; Laibson, 2002). With respect to risk preferences, experimental evidence shows that decisions depend not only on the discount factor (as the traditional model assumes) but also on prospect theory suggesting that risk preferences also depend on reference points (Kahneman & Tversky, 1979). Individuals classify gains and losses according to the level of protection on recent past or current status. Similarly, traditional economics assumes a purely self-interested consumer whose decisions depend uniquely on his own payoff, while charitable giving research, for example, finds that the utility function depends also on the payoffs for other people (Rose-Ackerman, 1996; Weisbrod, 1975; Newhouse, 1970). Second, regarding incorrect beliefs, behavioral economic theory suggests that specific beliefs modify decisions. In traditional theory, consumers have stable emotional states at the time of making decisions; however, experimental evidence suggests that individuals make decisions in different emotional states, and based on incorrect beliefs because of overconfidence, the law of small numbers and projection biases (DellaVigna, 2009; Read & Van Leeuwen, 1998; Rind, 1996). Third, there is evidence of the presence of systematic biases given that individuals project current outcomes and preferences on the future, expecting that future preferences will be similar to current ones. In this sense, the traditional theoretical view does not fully provide explanations to apparently irrational decisions, propelling social scientists to seek alternative explanations. Another view—the behavioral economics framework—has debated the traditional economic point of view suggesting that the rational model assumptions could be violated due to individual characteristics that influence choices. People generally tend to overestimate their own intelligence and business and planning skills (Camerer & Lovallo, 1999); they tend to over-project their current emotional state such as hunger or sexual arousal (Read & van Leeuwen, 1998; Ariely & Loewenstein, 2006); and they often use simple heuristics to solve complex problems (Gabaix et al., 2006, Tversky & Kahneman, 1974), and change their decisions based on transient emotions (Loewenstein & Lerner, 2003).

This conceptual framework, based on behavioral economics theory, has been summarized and popularized by publications such as Nudge: Improving Decisions about Health, Wealth, and Happiness (Thaler, 2008) and Thinking, Fast & Slow (Kahneman, 2013). This research suggests that human brains are complex and nuanced; that they make decisions not just based on careful utility calculations but also, for example, on who the messenger is; what they have just done or seen; and what is more relevant or salient at a particular juncture. In other words, human decisions are time inconsistent, influenced by frame and reference points, and may show a concern for the welfare of others (not just self).

Five main concepts from behavioral economics theory support the ubiquity of unhealthy behaviors. First, cognition (i.e., the mental process of acquiring knowledge that includes thinking, knowing, remembering, judging, and problem solving) is a particularly scarce element among people who have basic needs to satisfy first. This concept refers to the fact that human knowledge is limited and imperfect, and furthermore there is a large gap between cognition and action. Even when people know the facts about unhealthy options, they still engage in risk behaviors. Second, salience, which refers to choosing from options that seem more relevant when making a decision based on popularity, social media, or general trends. A salient feature stands out against a background of non-salient features. Individuals make decisions in contexts where salient features are desirable. Thus, they are prone to make decisions based on the relatively low importance of the (non-salient) concept of health in comparison to other features, which are perceived as most urgently needed (thus more salient). Processes based on passing trends do not necessarily lead to intentional, conscious, and controlled decision making (Taylor & Fiske, 1978). This is the case particularly among youth, who are generally highly concerned about what their peers or others may think (O’Donoghue & Rabin, 2001).

Third, present bias and myopic preferences arise when people attach more value to things that happen in the present or closer in time, and significantly less on those that happen in the future. Current consumption is usually biased toward immediate gratification, which often involves unhealthy behaviors, rather than health prevention or healthier options with delayed rewards. In the HIV field, riskier behavior arises when people attach more value to things that happen in the present and significantly less on those that happen in the future. One example is sex work in settings with low economic resources; there is clearly a problem of present bias because of immediate financial rewards attached to sex work. In interviews documented in Mexico City (Infante, Sosa-Rubi, & Cuadra, 2009) male sex workers mentioned their interest to earn more money in the short term through the supply of sex services. They heavily discounted the potential negative consequences of offering sexual services given the high risk of acquiring HIV and, hence, the health complications associated with the virus. Similarly, the clients who pay for sex also exhibit myopic preferences: they may feel that they generally do not want to engage in commercial sex; however, when arousal occurs, they give in and hire sexual services thinking of their own immediate sexual pleasure and not of HIV risk and other sexually transmitted infections (Monteiro et al., 2015).

Fourth, illusion versus reality: the underestimation of risks. In general, humans do not seem to have a good grasp of the underlying risks for most of their actions. They believe a bad outcome will not happen to them because they either do not know the risk, actively ignore it, or simply cannot change their course of action because they feel it is beyond their control (Tully, Cojocaru, & Bauch, 2015).

Fifth, over-optimism and framing. The first refers to the overconfidence about human capabilities, underestimating the potential consequences. O’Donoghue and Rabin (2001) find that over-optimism leads to a false perception of small costs of current sexual risk behavior in the present, which can lead to more severe repercussions in the future (e.g., the common practice of unprotected sex among young people). While the second, framing, alludes to the specific context in which individuals make decisions: young people, for example, tend to make decisions based on the behavior of the closest peers and the specific environment in which they develop (Bauermeister et al., 2009).

Tools to Change Behaviors

Different strategies in the area of prevention can reorient common behavior patterns to improve health. In the HIV field, several strategies have such purposes. Illustrative examples include: mobile messages to improve access to information (Mbuagbaw et al., 2015); motivation for linkage to HIV care (El-Sadr et al., 2017); reminders of medical appointments and adherence to treatment (Pop-Eleches et al., 2011, Bigna et al., 2014); prevention campaigns better customized and targeting specific needs for specific population groups (Wilson, Frade, Rech, & Friedman, 2016; Marie Apanovitch, McCarthy, & Salovey, 2003). In addition, provision of economic incentives in high-poverty settings can motivate vulnerable populations to use health services and nudge them toward healthier behaviors (Galárraga et al., 2017, Galárraga et al., 2018, Operario, Kuo, Sosa-Rubí, & Galárraga, 2013). Economic incentives become considerably more important in this context, given that poverty can compromise cognitive function, diminishing the capacity of recognizing the benefits of using preventative health services because of the common stress associated with day-to-day survival (Mani, Mullainathan, Shafir, & Zhao 2013). Aligning these evidence-based tools applied to the field of HIV with the theory of behavioral economics, we can summarize the strategies utilized according to each theoretical construct. Table 1 provides examples of specific strategies that have been implemented and evaluated that can be linked to different theoretical domains of behavioral economics.

Table 1. Summary of Behavioral Economics Mechanisms and Selected Examples

Tool

Description

Selected examples

Reminders

Reminders can help decrease the cognitive burden required to sequence or complete a complex task.

Pop-Eleches (2011): For improved adherence to ART, participants were provided with a mobile. Participants receiving weekly SMS reminders achieved adherence of at least 90% (Pop-Eleches et al., 2011).

Bigna (2014): For improved adherence to ART, appointment reminders were provided by text message, mobile phone call, or both. The most effective method of reminder was text message plus phone call, but text messaging alone was the most efficient (i.e., cost-effective) method.(Bigna et al., 2014)

Framing

The language used to describe a set of choices can shape people’s decision making. Framing can help when people misperceive risks by making certain outcomes more salient than others.

Friedman and Wilson (2015): For increased demand for a life-saving preventive health technology, a door-to-door marketing campaign randomly distributing 6,000 postcards to households. The framing advertisement device doubled demand for a life-saving health technology. (Friedman & Wilson, 2015)

Apanovitch (2003): For motivated HIV testing, videos were developed to control for any differences in the operationalization of message framing. Those who saw a gain-framed video reported a higher rate of testing than those who saw a loss-framed message. (Marie Apanovitch, McCarthy, & Salovey, 2003)

Labeling

Exploiting an individual’s “mental accounting” to encourage spending on investment goods that will benefit his or her own welfare.

Ammerman (2017): The Supplemental Nutrition Assistance Program (SNAP) (implemented in the United States for more than 75 years) uses behavioral strategies to promote healthy food choices (e.g., food stamps have been delivered more frequently throughout the month to promote purchasing of perishable products, such as fruits and vegetables) (Ammerman, Hartman, & DeMarco, 2017).

Salas (2015): For evaluating changes in savings accumulations of low income individuals, participants were led to label their savings. Savings accumulations increased by an average of 35%, and savings goals were 8.5% more likely to be reached in comparison to those untreated (Salas, 2015).

Micro-incentives

Token rewards, particularly those creating social recognition or salience, can be more motivating than the monetary value of the reward.

Ashraf (2014): For evaluating the effect of extrinsic rewards (financial and non-financial) to promote HIV prevention and sell condoms, stylists were provided with a thermometer display. Non-financial rewards are effective for improving performance; the effect of both types of rewards is stronger for pro-socially motivated agents; and both types of rewards are effective when their relative value is high. (Ashraf et al., 2014)

Ashraf (2014): For incentivizing performance in a health worker training program using non-monetary awards. Employer recognition and social visibility increase performance while social comparison reduces it, especially for low-ability trainees.(Ashraf et al., 2014b)

Social influences

Harnessing social norms or pressures to encourage beneficial decision making can be used to overcome biases in decision making.

De Dios (2013): Characterizes the structural and functional domains of social support in a sample of methadone maintenance treatment (MMT) smokers enrolled in a randomized smoking cessation clinical trial. The sample was characterized by relatively small social networks but high levels of general social support and quitting support.(de Dios et al., 2013)

Timing and salience information

People may process complex information more effectively if the information is presented in a targeted way, at a specific time, or through a particular agent.

Terris (2016): A static model differentiates drivers of demand for male and female condoms: Advertising is highly effective in raising demand for male but not female condoms; otherwise interpersonal communication is more potent for stimulating female condom demand also female condom demand is >3 times as sensitive as male condoms to price changes (Terris-Prestholt & Windmeijer, 2016).

Identity priming

Increasing the saliency of an individual’s gender, race, or role can be used to make certain choices (and their consequences) more salient.

McCoy (2017): A intervention to improve antiretroviral therapy (ART) adherence was developed using tools from marketing research and patient-centered design. A Baobab tree logo and a motto were designed to remind patients with HIV that they have a support system. Patients living with HIV infection exposed to the intervention were significantly more likely to be in care after six months and were more likely to achieve Medication Possession Ratio≥95% (McCoy et al., 2017).

Simplification

Making the terms/consequences of a decision more clearly understood at the correct moment in time can reduce the biases and cognitive costs of decision making.

Galárraga (2017): Computerized surveys that incorporated audio computer-assisted self-interviewing software (ACASI) minimized social desirability bias on sensitive questions about sex behavior (Galárraga et al., 2017).

Economic incentives

Pressing budgetary concerns leave fewer cognitive resources available to guide choice and action.

Rosen (2007): For improved adherence to prescribed antiretroviral medication, male and female patients with a history of substance use were randomized in two groups: supportive counseling and contingency management. A brief CM-based intervention was associated with significantly higher adherence and lower viral loads (Rosen et al., 2007).

El-Sadr (2017): For evaluating the effectiveness of financial incentives on linkage to care and viral suppression in HIV-positive individuals: Financial incentives did not increase linkage to care but significantly increased viral suppression (El-Sadr et al., 2017).

The use of reminders has been widely used to promote adherence to HIV treatment. This strategy helps to decrease the cognitive burden in patients who need to follow a sequence of daily tasks. Pop-Eleches et al. (2011) showed that automated text message reminders improve adherence among patients initiating ART in resource-limited settings. They specifically find that weekly SMS reminders increase the percentage of participants achieving 90% adherence to ART by approximately 13%–16% compared with no reminder. These weekly reminders are also effective at reducing the frequency of treatment interruptions, which are an important cause of treatment resistant failure in resource-limited settings.

Framing is useful in a context in which people misperceive risks by making certain outcomes more salient than others. O’Donoghue and Rabin (2001) exemplified this with the common false perception of the small costs of risky sexual behaviors in the present (without accounting for the non-negligible possibility of sexually transmitted infections and unplanned pregnancy). Strategies that have been implemented to overcome this misconception focus on using language that describes the choices more accurately. For example, a door-to-door marketing campaign to increase uptake of male circumcision (which protects against HIV and other sexually transmitted infections) randomly distributing 6,000 postcards to households in Soweto, South Africa, included a framing statement: “Are you tough enough?” The framing advertisement device doubled the demand for a life-saving health technology (Wilson et al., 2016, Friedman & Wilson, 2017).

One strategy not yet widely implemented is the use of social recognition to encourage beneficial decision making. In this context, social recognition points to the improvement of the self-esteem of individuals as consequence of publicly displaying certain characteristics or reaching specific achievements. Harnessing social norms and social recognition could be a mechanism to promote healthy behaviors. For example, in experimental studies, stylists and healthcare workers in Zambia were recognized with (non-monetary) social recognition awards in their communities for their achievements (Ashraf, Bandiera, & Jack, 2014; Ashraf, Bandiera, & Lee, 2014).

People may process complex information more effectively if the information is presented in a targeted manner, at a specific time, or through a particular agent. General health prevention campaigns could be less effective than those designed considering specific needs and characteristics of target groups. This idea references the concepts of timing, salience, and identity priming. For example, Terris-Prestholt and Windmeijer (2016) found that targeted advertising is highly effective in raising demand for male condoms, while interpersonal communication is more potent for stimulating female condom demand. One outstanding example of priming is the intervention implemented by McCoy et al. (2017) in Tanzania, where they use the image of a Baobab tree (the “tree of life”), a positive image known by habitants in Shinyanga as a symbol of life and positivity. The tree logo and motto were designed to remind patients with HIV that they have a support system.

Rationality in decision making is bounded by factors such as lack of information, cognitive limitations, and a finite amount of time to make a decision. People may lack discipline and can experience decision fatigue (Matjasko, Cawley, Baker-Goering, & Yokum, 2016). In the context of health services use, simplifying how information is presented and the process of health service access can help overcome the obstacles experienced by vulnerable populations. For instance, sex workers in Mexico City, as part of a randomized pilot study, were supported to follow all the procedures to be registered in the HIV clinic in order to improve their linkage to HIV prevention services (Galárraga et al., 2017).

Another aspect is the consequences of living with limited resources, which limits the priorities of individuals making a decision. Preoccupation with pressing budgetary concerns leaves fewer cognitive resources available to guide choices and actions. Poverty-related concerns and day-to-day stress, consume a higher level of mental resources, displacing other relevant future-related tasks. Individuals living in these conditions make decisions based on immediate rewards rather than the future cost of their present choices (Mani et al., 2013). There is body of evidence about the considerable benefits generated by the provision of small amounts of economic incentives to populations living under poverty conditions (Skoufias, 2010; Ham & Michelson, 2018; Martinez Cotto, 2018; Saavedra). In this context, small conditional economic incentives could be promising in HIV prevention and treatment programs because they can address behavioral shortcomings particularly in the short term.

Recognizing the need to nudge individuals to increase use of HIV health services, adherence to HIV treatment, and reduce risky sexual behaviors, several HIV interventions have been designed to use economic incentives as a powerful tool, as it will be detailed in the next section.

Economic Incentives as Part of HIV Interventions to Change Behaviors

This section selectively reviews economic incentives as behavior change tools specifically applied to improve HIV prevention and treatment outcomes. Given the importance of STIs, and HIV in particular, conditioned incentives have received sustained and renewed attention in the literature (Haug & Sorensen, 2006; Sorensen et al., 2007; Kamb et al., 1998).

Economic incentives to modify behaviors in the HIV field have been analyzed since the early 2000s. Most of the studies in high-income countries were implemented in the United States and focused on improving adherence to HIV treatment among adults. Rigsby et al. (2000) randomized 55 infected subjects on stable ART regimens in the United States and show that adherence is significantly enhanced in the group with cue-dose training and cash reinforcements compared to the control group receiving cue-dose training only. The economic incentive consisted of incremental cash reinforcement from US$2 to a maximum of US$10. Javanbakht et al. (2006) evaluate the effectiveness of economic incentives on improving adherence to antiretroviral therapy among 90 HIV-positive patients with poor adherence. Providing US$20 reimbursed in each monthly follow-up visit, they find reductions in viral load, measured through HIV-1 RNA levels and CD4 counts, among the group of patients who received cash transfers. Rosen et al. (2007) found greater adherence and lower viral load among HIV-positive patients with a history of substance abuse. Incentives consisted of lottery vouchers with a value of US$1, US$20, and US$100 plus a payment of US$325 to those participants who finished the study. Another contingency management intervention was carried out in 2007 in the United States among HIV-positive patients enrolled in methadone maintenance treatment (Sorensen et al., 2007). A US$50 voucher per dose for medications taken twice daily was granted to patients. The value of the voucher increased for each consecutive day of uninterrupted HIV medication intake. As in other studies, adherence is significantly enhanced in the treatment group compared to the control group. In another study of financial incentives to increase adherence to HIV treatment in the United States, quarterly payments of $100 were contingent on an “either/or” reward criterion. Patients need to either (Dick, Ferguson, & Ross, 2006) suppress their plasma HIV RNA below the lower limit of detection, or (Rotheram-Borus, 2000) demonstrate a viral load that is at least one log10 lower than their prior lowest viral load in the past year. Among individuals with detectable viral loads pre-intervention, the proportion of undetectable viral load tests increases from 57% to 69% before versus after the intervention (Farber et al., 2013). Finally, in a randomized study among HIV-positive individuals (El-Sadr et al., 2017), incentives of $125 cash-equivalent gift cards are provided to patients who test HIV positive and link to care and $70 gift cards for HIV-positive patients receiving ART, if they demonstrate viral suppression. Financial incentives significantly increase viral suppression and regular clinic attendance among HIV-positive patients.

More recent studies have been undertaken in low- and middle-income countries in generalized and concentrated HIV epidemic settings. These studies focus mainly on analyzing the effects of financial incentives on vulnerable groups of the population. The first study was developed in Malawi (Thornton, 2008), where monetary incentives were used to increase return rates to learn results from HIV testing. The study randomizes vouchers after individuals are tested for HIV and STIs. Vouchers are granted after a lottery and range from US$0 to US$3. Any incentive more than doubles the baseline rate (of 34%) to return to learn HIV status. Moreover, HIV-positive individuals who learn their result are three times more likely to purchase condoms two months later. Another study also in Malawi, but targeting adolescent girls and young women, provides conditional and unconditional economic incentives for school attendance as first outcome and reduce HIV prevalence as second outcome. Receipt of conditional cash transfers (CCT) was conditional on at least 80% school attendance. The study finds that HIV prevalence is lower in the group with unconditional cash transfers (UCT) (2%) and CCT (1%) groups compared with the control group (3%). This effect is similar in herpes virus type-2 (HSV-2) prevalence. For dropout girls, both UCT and CCT incentives improve school attendance (57%) compared with control group (12%) (Baird, Garfein, McIntosh, & Özler, 2012). Similarly, another trial in South Africa provides monthly cash transfers to young women (US$10) for school attendance and to their parents or guardians (US$20). The authors find that economic incentives increase the likelihood of school attendance significantly, which indirectly reduce risk of HIV acquisition, irrespective of study group (Pettifor et al., 2016). De Walque et al. (2012) use cash transfers for HIV and sexually transmitted infection (STI) prevention among young adults in rural Tanzania. They provide a low-value (US$10 per STI testing round) and high-value (US$20 per STI testing round) incentive conditional on staying negative for curable STIs. Prevalence of combined STIs is lower in the high-value arm compared to controls. In addition, a study implemented in Chennai, India, uses incentives in the form of vouchers with a value of US$4 and US$8 to increase linkage and retention in HIV care among drug users. The authors find that modest voucher incentives improve linkage to and retention in HIV care but do not significantly impact viral suppression (Suhas Solomon et al., 2014). Finally, a study in Cape Town, South Africa, provides an incentive of US$23 to link to care right after the initial HIV diagnosis (Maughan-Brown et al., 2018). It does not improve the linkage rates, nor does it speed up the linkage process. It is particularly cumbersome even when patients do want to link to care faster (Maughan-Brown et al., 2018; Maughan-Brown et al., 2018b). Björkman-Nyqvist, Corno, de Walque, and Svensson (2016) implement an intervention to reduce HIV incidence. Individuals in intervention groups win lottery prizes worth US$50 and US$100 every four months conditional on being free of STIs. The authors find a reduction of 21.4% in HIV incidence over two years of follow-up; however, HIV incidence rates increase by 2.7 percentage points in both intervention groups in the year following the trial. Economic incentives were granted in Kenya (Thirumurthy et al., 2014) to promote voluntary medical male circumcision in men within two months. The intervention group receives food vouchers with varying amounts (US$3, US$9, or US$15) while the control group does not receive any compensation. This results in a modest increase in the prevalence of circumcision after two months of follow-up. Finally, incentives or lotteries were granted to participants if they visit a primary healthcare clinic for HIV testing. Both fixed incentives and lottery-based incentives increase the uptake of HIV testing among children and adolescents (8 to 17 years old) (Kranzer et al., 2017). In a pilot study implemented in Mexico (Galárraga et al., 2017), 227 male sex workers (MSWs) were randomized into four groups: control (no incentives), medium incentive conditional on staying free of new curable STIs (US$50), high incentive conditional on staying free of new curable STIs (US$75), and medium incentive (US$50) conditional only on study visit attendance. The authors find that conditional economic incentives for MSWs increase linkage to care and retention and contribute to reduce HIV/STIs through increased condom use.

Sustainability of the Effects of Economic Incentives Over Time

There is limited evidence regarding the sustainability of behavior change once the economic incentives are removed. In the area of promoting adherence to treatment it has been proven (over decades of research and in a variety of settings) that incentives generally provide immediate benefits for consistent medication adherence. However, this does not necessarily create a lasting effect after the incentives are removed (Galárraga et al., 2013). Similar results have been found in other areas such as regular attendance to HIV prevention services by MSWs (Galárraga et al., 2017) even when incentive levels are carefully designed ex-ante (Galárraga et al., 2014), as well as other cash incentive interventions (Baird et al., 2016).

One criticism emerged from self-determination theory (SDT) (Igreja et al., 2000), which emphasizes the importance of supporting natural or intrinsic characteristics of individuals to behave in effective and healthy ways (rather than on extrinsic motivators such as material incentives). In this sense, SDT underlines that economic incentives may be ignoring the motivational structure underlying choices related to healthy or unhealthy behaviors. According to this view, imposing artificial external rewards is not enough to make a healthy behavior habitual and sustained. Mechanisms to internalize the motivation are needed rather than only external incentives in order to achieve long-term behavioral change. There are dissenting opinions, however, about this general claim (Cameron, 2001; Cameron et al., 2001; David Pierce, Cameron, Banko, & So, 2003), and the hypothesis has not been directly tested in the context of HIV.

Table 2. Selected Randomized Controlled Trials of Conditional Economic Incentives to Improve HIV Prevention and Treatment

First author, year, country

Population & Setting

CEI Incentive

Results

Effect Maintenance Follow-up

Sustainability of the effects of EI over time

Rigsby (2000), United States (Rigsby et al., 2000)

n=55 HIV infected male and female subjects on stable ART regimens randomly assigned to a control training group, a cue-dose training group and a cue-dose training plus cash reinforcement group.

Incremental cash reinforcement from US$2 to a maximum to US$10 for correct intake of medication

Adherence was significantly enhanced in the group with cue-dose training and cash reinforcement

Yes

In the follow up period, eight weeks after training and reinforcement were discontinued, adherence in the cash reinforced group returned to near-baseline levels.

Javanbakht (2006), United States (Javanbakht et al., 2006)

n=90 HIV-positive patients (male and female) experiencing treatment failure randomly assigned to an adherence case management intervention with monetary reinforcement or to a standard of care group.

Monthly cash transfer for reduce viral load: US$20 reimbursed in each monthly follow-up visits

An individualized adherence intervention with monetary reinforcement is feasible and effective in reducing viral load and improving immune function.

Yes

Effects were apparent by three months after the initiation of the program and were maintained after completion of the intensive phase of the program at months 6 and 12.

Rosen (2007), United States (Rosen et al., 2007)

N=56 HIV-infected male and female patients with history of substance use randomized in two groups: supportive counseling and contingency management

Vouchers with variable value between US$1 and US$100 plus a payment of US$325 to those participants who finished the study and taken medication correctly.

Contingency management-based intervention was associated with significantly higher adherence and lower viral loads.

Yes

By the end of the 16-week follow-up phase, differences between groups in adherence and viral load were no longer significantly different.

Sorensen (2007), United States (Sorensen et al., 2007)

N=66 male and female patients enrolled in methadone maintenance treatment randomly assigned to comparison group or voucher group

A US$.50 voucher per dose for medications taken twice daily. Value of voucher increased for each consecutive day of uninterrupted medication intake.

Adherence was significantly enhanced in the intervention group.

Yes

Adherence improvements were not sustained during the follow-up period (four weeks), and the study did not show an effect of improved adherence on viral load.

Thornton (2008), Malawi (Thornton, 2008)

n=2812 male and female individuals in randomized lottery of vouchers after tested for HIV or/and STIs

Among participants who taken HIV test, vouchers ranged between zero and three dollars were randomized by letting each individual draw a token out of a bag indicating a monetary value

HIV-positive individuals who learned their results were more likely to purchase condoms than sexually active HIV-positive individuals who did not learn their results. HIV-positive individuals who learned their results purchase two additional condoms than those who did not.

Yes

There was no significant effect of learning HIV-negative results on the purchase of condoms or on the likelihood of having sex two months (follow-up period) after learning HIV-negative results.

De Walque (2012), Tanzania (De Walque et al., 2012)

n=2399 males and females aged 18 to 30 years randomized in a control arm or one of two intervention arms: low-value conditional cash transfer and high-value conditional cash transfer.

Conditional cash transfer: low-value (US$10 per testing round) and high-value (US$20 per testing round) for negative status of STIs.

Financial incentives reduced the prevalence of STIs.

No

NA

Baird (2012), Malawi (Baird et al., 2012)

n= 3796 never-married girls aged 13–22 years randomly assigned to intervention (conditional and unconditional cash transfer) or control group. Each group (CCT, UCT and control group) has two subgroups: baseline dropouts and baseline schoolgirls.

In the CCT group (baseline schoolgirls and baseline dropouts), monthly cash transfers were provided for school attendance maintenance: amount varied randomly between individuals with monthly values of US$1, US$2, US$3, US$4, or US$5.

Cash transfers decreased risky sexual activity and reduce likelihood of HIV and HSV-2 infection

Yes

The effect of the incentives was analyzed 18 months before the incentives were withdrawn (the incentives were provided for two years). Changes in self-reported sexual behavior were reported: prevalence of HIV and HSV-2 decreased in schoolgirls.

Farber (2013), United States (Farber et al., 2013)

n=69 Individuals in ART with detectable viral load and 12 months follow up. Each patient was used as his own control.

Quarter monetary payment (US$100) contingent on an “either/or” reward criterion: patients needed to either (1) achieve undetectable viral load, or (2) reduce (at least one log10) viral load.

Proportion of undetectable viral load tests increased from 57% to 69% before versus after the intervention.

No

NA

Solomon (2014), India.(Suhas Solomon et al., 2014)

N=120 HIV-infected drug users (mostly men) were randomly assigned to the incentive arm or the control arm.

Vouchers for specific targets: One voucher (4 USD dollars) for initiate ART; 12 (maximum) vouchers (US$4) if patient visited HIV clinic for clinical care/refill; and 2 (maximum) vouchers (US$8) for HIV RNA suppression.

Modest voucher incentives improved linkage to and retention in HIV care, but did not significantly impact viral suppression

No

NA

Pettifor (2016), South Africa (Pettifor et al., 2016)

n=2537 girls aged 13–20 years randomly assigned in two groups: cash transfer conditional group and no cash transfer group.

Monthly cash transfer for school attendance maintenance: US$10 for young women and US$20 for their parents or guardians.

CCT on school attendance did not reduce HIV incidence in young women. School attendance significantly reduced risk of HIV acquisition, irrespective of study group.

No

NA (There was no effect of the incentive during the intervention, therefore, neither in the follow-up).

Björkman (2016), Lesotho (Björkman-Nyqvist et al., 2016)

n= 3,029 males and females (HIV-positive or -negative) residents of Lesotho between 18–32 years were randomized in three groups: low-value lottery, high- value lottery and a control group.

Individuals in intervention groups were eligible to win lottery prizes worth approximately US$50 and US$100 (in low-value and high-value lottery groups, respectively) every four months conditional on being tested negative for two STIs. Lottery drawings were organized every four months in each village; four lottery winners (one male and one female per lottery arm) per village were drawn.

A reduction of 21.4% in HIV incidence was observed over two years. The model proposed estimates that risk-loving individuals reduce the number of unprotected sexual acts by 0.3/month for every US$1 increase in the expected prize.

Yes

HIV incidence rates were similar across intervention groups in the year following the trial and the STI prevalence rate increased by 2.7 percentage points in both intervention groups, there is no evidence of adverse reactions or consequences in the intervention relative the control group, at least based on data one year after the intervention ended.

Baird (2016), Malawi (Baird et al., 2016)

n= 3796 never-married girls aged 13–22 years randomly assigned to intervention (conditional and unconditional cash transfer) or control group. Each group (CCT, UCT, and control group) has two subgroups: baseline dropouts and baseline schoolgirls.

In the CCT group (baseline schoolgirls and baseline dropouts), girls received transfer amounts—ranging from US$1 and US$5, in a public lottery for school attendance maintenance.

Significant declines in HIV prevalence, teen pregnancy, and early marriage among recipients of UCTs. CCTs offered to out-of-school females at baseline produced a large increase in educational attainment and a sustained reduction in the total number of births, but caused no gains in health, labor market outcomes, or empowerment.

Yes

Short-term improvements in the UCT arm observed during and at the end of the program failed to translate into increased welfare in the long run (a large number of UCT beneficiaries became pregnant and were married soon thereafter). CCTs caused sustained effects on school attainment, incidence of marriage and pregnancy, age at first birth, total number of births, and desired fertility (in the dropout subgroup).

El-Sadr (2017), United States (El-Sadr et al., 2017)

37 HIV test and 39 HIV care sites in two U.S. cities of were randomized to financial incentives or standard of care.

US$125 cash-equivalent gift cards for patients tested HIV-positive and US$70 gift cards for HIV- positive patients receiving ART

Financial incentives significantly increased viral suppression and regular clinic attendance among HIV-positive patients. Financial incentives did not have a significant effect on linking HIV-positive individuals to care.

No

NA

Galárraga (2017), Mexico (Galárraga et al., 2017)

n = 227 MSWs were randomized into four groups: control, two groups for medium incentives, and high incentives

Medium incentive (1): US$50 in the form of supermarket vouchers at visits 6 and 12 months for negative status of STIs. . High incentive: US$75 in the form of supermarket vouchers at visits 6 and 12 months for negative status of STIs. No CEIs were provided at the 18-month assessment.

Conditional incentives for male sex workers can increase linkage to care and retention and reduce some HIV/STI risks such as condom-less sex, while incentives are in place.

No

NA

Thirumurthy (2017), Kenya (Thirumurthy et al., 2014)

n= 1504 uncircumcised men aged 25 to 49 years were randomized to one of three intervention groups or a control group.

Economic incentives were granted to promote circumcision in men within two months. Participants in the intervention groups received food vouchers with varying amounts: ≈US US$2.50, ≈US US$8.75, or ≈US$15, which reflected a portion of transportation costs and lost wages associated with getting circumcised. The control group received no compensation.

Among uncircumcised men in Kenya, compensation in the form of food vouchers worth approximately US$8.75 or US$15, compared with lesser or no compensation, resulted in a modest increase in the prevalence of circumcision after 2 months.

No

NA

Kranzer (2018), Zimbabwe (Kranzer et al., 2017)

n= 2050 eligible households were randomly assigned (1:1:1) to one of three groups: no incentive, fixed incentive and lottery.

US$2 fixed incentive or lottery (cash prize of US$5 or US$10) were assigned if a survey participant in the household presented to the primary healthcare clinic in the study community for HIV testing.

Fixed incentives and lottery-based incentives increased the uptake of HIV testing by older children and adolescents, a key hard-to-reach population. This strategy would be sustainable in the context of vertical HIV infection as repeated testing would not be necessary until sexual debut.

No

NA

Future Directions and Policy Recommendations

This article provides general considerations for the design of effective HIV prevention and treatment interventions using conditional economic incentives. First, the benefits of small and frequent conditional economic incentives for vulnerable populations are confirmed by several studies. Yet the idea that they can contribute to a sustained improvement in behavior change over time is still not fully supported. Second, it sheds further light on the importance of the design of combined strategies that provide vulnerable individuals with the tools for overcoming the decision-making biases influencing important choices that affect their health. Economic incentives accompanied with other strategies can help overcome obstacles to access health services and seem to generally improve linkage to care, prevention interventions, and adherence to HIV treatment. Identifying promising combinations of intervention components, modalities, and strategies will be more likely to yield maximum impact on behavioral decisions in the future. Lastly, the extant literature suggests, collectively the effectiveness of HIV prevention and treatment interventions using incentives depends on various parameters including the target population, the type of conditionality, and the size and modality of the incentive. These choices can have important implications in the intermediate mechanisms and ultimate results. Hence, future emphasis should be placed on theory-based and carefully implemented economic-based interventions to improve HIV prevention and treatment outcomes.

Further Reading

Cameron, J. (2001). Negative effects of reward on intrinsic motivation: A limited phenomenon: Comment on Deci, Koestner, and Ryan (2001). Review of Educational Research, 71(1), 29–42.Find this resource:

Cameron, J., Banko, K. M., & Pierce, W. D. (2001). Pervasive negative effects of rewards on intrinsic motivation: The myth continues.The Behavior Analyst, 24(1), 1–44.Find this resource:

David Pierce, W., Cameron, J., Banko M., & So, S. (2003). Positive effects of rewards and performance standards on intrinsic motivation. Psychological Record, 561–578.Find this resource:

DellaVigna, S. (2009). Psychology and economics: Evidence from the field. Journal of Economic Literature, 47(2), 315–372.Find this resource:

Galárraga, O., Genberg, B. L., Martin, R. A., Barton Laws, M., & Wilson, I. B. (2013). Conditional economic incentives to improve HIV treatment adherence: Literature review and theoretical considerations. AIDS Behavior, 17(7), 2283–2292.Find this resource:

Ham, A., & Michelson, H. (2018). Does the form of delivering incentives in conditional cash transfers matter over a decade later? Journal of Development Economics, 134, 96–108.Find this resource:

Kahneman, D. (2013). Thinking, fast and slow. New York, NY: Farrar, Straus and Giroux. First Edition, 499.Find this resource:

Lagarde, M., Haines, A., & Palmer, N. (2007). Conditional cash transfers for improving uptake of health interventions in low- and middle-income countries: A systematic review. Journal of the American Medical Association, 1900–1910.Find this resource:

Loewenstein, G., & Lerner, J. S. (2003). The role of affect in decision making. In R. Davidson, H. Goldsmith, K. Scherer (Eds.), Handbook of affective science (pp. 619–642). Oxford, U.K.: Oxford University Press.Find this resource:

Mani, A., Mullainathan, S., Shafir, E., & Zhao, J. (2013). Poverty impedes cognitive function. Science, 341(6149), 976–980.Find this resource:

Martinez Cotto, S. A. (2018). The effect of cash transfer programs on poverty reduction. Bussiness and Public Administration Studies, 12(1), 1–9.Find this resource:

O’Donoghue, T., & Rabin, M. (1999). Doing it now or later. American Economic Review, 89(1), 103–124.Find this resource:

O’Donoghue, T., & Rabin, M. (2001). Choice and procrastination. Quarterly Journal of Economics., 116(1), 121–160.Find this resource:

Operario, D., Kuo, C., Sosa-Rubí, S. G., & Galárraga, O. (2013, September). Conditional economic incentives for reducing HIV risk behaviors: Integration of psychology and behavioral economics. Health Psychology, 32(9), 932–940.Find this resource:

Saavedra, J. (2016). The effects of conditional cash transfer programs on poverty reduction, human capital accumulation and wellbeing, 1–10.Find this resource:

Taylor, S., & Fiske, S. (1978). Salience, attention, and attribution: Top of the head phenomena. Advances in Experimental Social Psychology, 249–288.Find this resource:

Thaler, R. H. (2008). Nudge: Improving decisions about health, wealth, and happiness. New Haven, CT: Yale University Press.Find this resource:

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