The controversy over how much to charge for health products in the developing world rests, in part, on whether higher prices can increase use, either by targeting distribution to high-use households (a screening effect), or by stimulating use psychologically through a sunk-cost effect. We develop a methodology for separating these two effects. We implement the methodology in a field experiment in Zambia using door-to-door marketing of a home water purification solution. We find evidence of economically important screening effects. By contrast, we find no consistent evidence of sunk-cost effects. (JEL C93, D12, I11, M31, O12)

The promise of randomized controlled trials is that evidence gathered through the evaluation of a specific program helps us-possibly after several rounds of fine-tuning and multiple replications in different contexts-to inform policy. However, critics have pointed out that a potential constraint in this agenda is that results from small "proof-of-concept" studies run by nongovernment organizations may not apply to policies that can be implemented by governments on a large scale. After discussing the potential issues, this paper describes the journey from the original concept to the design and evaluation of scalable policy. We do so by evaluating a series of strategies that aim to integrate the nongovernment organization Pratham's "Teaching at the Right Level" methodology into elementary schools in India. The methodology consists of reorganizing instruction based on children's actual learning levels, rather than on a prescribed syllabus, and has previously been shown to be very effective when properly implemented. We present evidence from randomized controlled trials on the designs that failed to produce impacts within the regular schooling system but helped shape subsequent versions of the program. As a result of this process, two versions of the programs were developed that successfully raised children's learning levels using scalable models in government schools. We use this example to draw general lessons about using randomized control trials to design scalable policies.

We utilize the Becker-DeGroot-Marschak (1964) mechanism to estimate the willingness to pay for clean drinking water technology in northern Ghana. The BDM mechanism has attractive properties for empirical research, allowing us to directly estimate demand, compute heterogeneous treatment effects, and study the screening and causal effects of prices with minor modifications to a standard field experiment setting. We demonstrate the implementation of BDM along these three dimensions, compare it to the standard take-it-or-leave it method for eliciting willingness to pay, and discuss practical issues for implementing the mechanism in true field settings.

The promise of randomized controlled trials is that evidence gathered through the evaluation of a specific program helps us—possibly after several rounds of fine-tuning and multiple replications in different contexts—to inform policy. However, critics have pointed out that a potential constraint in this agenda is that results from small “proof-of-concept” studies run by nongovernment organizations may not apply to policies that can be implemented by governments on a large scale. After discussing the potential issues, this paper describes the journey from the original concept to the design and evaluation of scalable policy. We do so by evaluating a series of strategies that aim to integrate the nongovernment organization Pratham’s “Teaching at the Right Level” methodology into elementary schools in India. The methodology consists of reorganizing instruction based on children’s actual learning levels, rather than on a prescribed syllabus, and has previously been shown to be very effective when properly implemented. We present evidence from randomized controlled trials involving some designs that failed to produce impacts within the regular schooling system but still helped shape subsequent versions of the program. As a result of this process, two versions of the programs were developed that successfully raised children’s learning levels using scalable models in government schools. We use this example to draw general lessons about using randomized control trials to design scalable policies.

The promise of randomized controlled trials is that evidence gathered through the evaluation of a specific program helps us-possibly after several rounds of fine-tuning and multiple replications in different contexts-to inform policy. However, critics have pointed out that a potential constraint in this agenda is that results from small "proof-of-concept" studies run by nongovernment organizations may not apply to policies that can be implemented by governments on a large scale. After discussing the potential issues, this paper describes the journey from the original concept to the design and evaluation of scalable policy. We do so by evaluating a series of strategies that aim to integrate the nongovernment organization Pratham's "Teaching at the Right Level" methodology into elementary schools in India. The methodology consists of reorganizing instruction based on children's actual learning levels, rather than on a prescribed syllabus, and has previously been shown to be very effective when properly implemented. We present evidence from randomized controlled trials on the designs that failed to produce impacts within the regular schooling system but helped shape subsequent versions of the program. As a result of this process, two versions of the programs were developed that successfully raised children's learning levels using scalable models in government schools. We use this example to draw general lessons about using randomized control trials to design scalable policies.