Does completing a household survey change the later behavior of those surveyed? In three field studies of health and two of microlending, we randomly assigned subjects to be surveyed about health and/or household finances and then measured subsequent use of a related product with data that does not rely on subjects' selfreports. In the three health experiments, we find that being surveyed increases use of water treatment products and take-up of medical insurance. Frequent surveys on reported diarrhea also led to biased estimates of the impact of improved source water quality. In two microlending studies, we do not find an effect of being surveyed on borrowing behavior. The results suggest that limited attention could play an important but context-dependent role in consumer choice, with the implication that researchers should reconsider whether, how, and how much to survey their subjects. measurement effects | question-behavior effects | Hawthorne effects | survey methodology | models of attention M any data collection efforts in the social and clinical sciences rely on surveys. Psychologists and marketing and survey experts have long held that surveying a subject can draw attention to risks or choices with ordinarily little salience and thereby induce changes in subsequent behavior (1, 2), but conclusive evidence on this question from which a causal relationship can be clearly established has been limited. We provide evidence from a variety of settings that the act of being surveyed can affect behavior and confound estimates of parameters that initially motivated the data collection."Survey" or "interview" effects may occur even when the survey does not ask specifically about intent to engage in the behavior of interest or provide new information, and even when subjects do not know that their later behavior is being observed by researchers. Hence survey effects are conceptually distinct from, but closely related to, "question-behavior" (i.e., mere measurement or self-prophecy) and Hawthorne effects. Question-behavior effects arise when behavior changes as a result of asking subjects for intentions or predictions regarding future behavior effects (3-6). Hawthorne effects occur when behavior changes as a result of a subject responding to being treated and observed, as part of an experiment (7). These effects are also related to "push polling" and other efforts to manipulate subject behavior by posing hypothetical questions (8).We describe results from five different field experiments, in four developing countries, on whether being surveyed affects subsequent behavior. The first experiment randomizes the frequency of surveys on health behavior and diarrhea incidence, in a context in which other water quality interventions are also randomly provided. More-frequent surveying leads to lower reported child diarrhea and cleaner water (as measured by the presence of detectable chlorine in household drinking water). We posit that frequent surveying serves as a reminder to invest in water purification, although because sub...

In many societies, social norms create common property rights in natural resources, limiting incentives for private investment. This paper uses a randomized evaluation in Kenya to measure the health impacts of investments to improve source water quality through spring protection, estimate the value that households place on spring protection, and simulate the welfare impacts of alternative water property rights norms and institutions, including common property, freehold private property, and alternative "Lockean" property rights norms. We find that infrastructure investments reduce fecal contamination by 66% at naturally occurring springs, cutting child diarrhea by one quarter. While households increase their use of protected springs, travel-cost based revealed preference estimates of households' valuations are only one-half stated preference valuations and are much smaller than levels implied by health planners' typical valuations of child mortality, consistent with models in which the demand for health is highly income elastic. Simulations suggest that, at current income levels, private property norms would generate little additional investment while imposing large static costs due to spring owners' local market power, but that private property norms might function better than common property at higher income levels. Alternative institutions, such as "modified Lockean" property rights, government investment or vouchers for improved water, could yield higher social welfare.

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This paper uses a public economics framework to review evidence from randomized trials on domestic water access and quality in developing countries and to assess the case for subsidies. Water treatment can cost-effectively reduce reported diarrhea. However, many consumers have low willingness to pay for cleaner water; few households purchase household water treatment under retail models. Free point-of-collection water treatment systems designed to make water treatment convenient and salient can generate take-up of approximately 60% at a projected cost as low as $20 per year of life saved, comparable to vaccine costs. In contrast, the limited existing evidence suggests that many consumers value better access to water, but it does not yet demonstrate that better access improves health. The randomized impact evaluations reviewed have also generated methodological insights on a range of topics, including (a) the role of survey effects in health data collection, (b) methods to test for sunk-cost effects, (c) divergence in revealed preference and stated preference valuation measures, and (d) parameter estimation for structural policy simulations.

Using a randomized evaluation in Kenya, we measure health impacts of spring protection, an investment that improves source water quality. We also estimate households' valuation of spring protection and simulate the welfare impacts of alternatives to the current system of common property rights in water, which limits incentives for private investment. Spring infrastructure investments reduce fecal contamination by 66%, but household water quality improves less, due to recontamination. Child diarrhea falls by one quarter. Travel-cost based revealed preference estimates of households' valuations are much smaller than both stated preference valuations and health planners' valuations, and are consistent with models in which the demand for health is highly income elastic. We estimate that private property norms would generate little additional investment while imposing large static costs due to above-marginal-cost pricing, private property would function better at higher income levels or under water scarcity, and alternative institutions could yield Pareto improvements.