Previous measures of physical activity for epidemiologic studies were considered inadequate to meet the needs of a community-based health education trial. Therefore, new methods of quantifying the physical activity habits of communities were developed which are practical for large health surveys, provide information on the distribution of activity habits in the population, can detect changes in activity over time, and can be compared with other epidemiologic studies of physical activity. Independent self-reports of vigorous activity (at least 6 metabolic equivalents (METs) ), moderate activity (3-5 METs), and total energy expenditure (kilocalories per day) are described, and the physical activity practices of samples of California cities are presented. Relationships between physical activity measures and age, education, occupation, ethnicity, marital status, and body mass index are analyzed, and the reliabilities of the three activity indices are reported. The new assessment procedure is contrasted with nine other measures of physical activity used in community surveys.

We document three remarkable features of the Opower program, in which social comparison-based home energy reports are repeatedly mailed to more than six million households nationwide. First, initial reports cause high-frequency "action and backsliding," but these cycles attenuate over time. Second, if reports are discontinued after two years, effects are relatively persistent, decaying at 10-20 percent per year. Third, consumers are slow to habituate: they continue to respond to repeated treatment even after two years. We show that the previous conservative assumptions about post-intervention persistence had dramatically understated cost effectiveness and illustrate how empirical estimates can optimize program design.

The fact that many citizens fail to vote is often cited to motivate others to vote. Psychological research on descriptive social norms suggests that emphasizing the opposite-that many do vote-would be a more effective message. In two get-out-the-vote field experiments, we find that messages emphasizing low expected turnout are less effective at motivating voters than messages emphasizing high expected turnout. The findings suggest that descriptive social norms affect vote intention only among citizens who vote infrequently or occasionally. Practically, the results suggest that voter mobilization efforts should emphasize high turnout, especially when targeting occasional and low rate of participation voters. More generally, our findings suggest that the common lamentation by the media and politicians regarding low participation may undermine turnout.

We document three remarkable features of the Opower program, in which social comparison-based home energy reports are repeatedly mailed to more than six million households nationwide. First, initial reports cause high-frequency “action and backsliding,” but these cycles attenuate over time. Second, if reports are discontinued after two years, effects are relatively persistent, decaying at 10–20 percent per year. Third, consumers are slow to habituate: they continue to respond to repeated treatment even after two years. We show that the previous conservative assumptions about post-intervention persistence had dramatically understated cost effectiveness and illustrate how empirical estimates can optimize program design.(JEL D12, D83, L94, Q41)

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