An inherent problem in measuring the influence of expert reviews on the demand for experience goods is that a correlation between good reviews and high demand may be spurious, induced by an underlying correlation with unobservable quality signals. Using the timing of the reviews by two popular movie critics, Siskel and Ebert, relative to opening weekend box office revenue, we apply a difference-in-differences approach to circumvent the problem of spurious correlation. After purging the spurious correlation, the measured influence effect is smaller though still detectable. Positive reviews have a particularly large influence on the demand for dramas and narrowly-released movies.

Several papers have documented that when subjects play with standard laboratory "endowments" they make less self-interested choices than when they use money they have either earned through a laboratory task or brought from outside the lab. In the context of a charitable giving experiment we decompose this into two common artifacts of the laboratory: the intangibility of money (or experimental currency units) promised on a computer screen relative to cash in hand, and the distinct treatment of random "windfall" gains relative to earned money. While both effects are found to be significant in non-parametric tests, the former effect, which has been neglected in previous studies, has a stronger impact on total donations, while the latter effect has a greater impact on the probability of donating. These results have clear implications for experimental design, and also suggest that the availability of more abstract payment methods may increase other-regarding behavior in the field.

Previous experimental and observational work suggests that people act more generously when they are observed and observe others in social settings. However, the explanation for this is unclear. An individual may want to send a signal of her generosity to improve her own reputation. Alternately (or additionally) she may value the public good or charity itself and, believing that contribution levels are strategic complements, give more to influence others to give more. We perform the first series of laboratory experiments that can separately estimate the impact of these two social effects, and test whether realized influence is consistent with the desire to influence, and whether either of these are consistent with anticipated influence. Our experimental subjects were given the opportunity to contribute from their endowment to Bread for the World, a development NGO. Depending on treatment, "leader" subjects' donations were reported to other subjects either anonymously or with their identities, and these were reported either before these "follower" subjects made their donation decisions. We find that "leaders" are influential only when their identities are revealed along with their donations, and female leaders are more influential than males. Identified leaders' predictions suggest that are aware of their influence. They respond to this by giving more than either the control group or the unidentified leaders. We find mixed evidence for "reputation-seeking." Electronic supplementary material The online version of this article (

This paper defines, discusses, and measures “expenditure substitution” in charitable giving. Motivated by a model of conditional demand, I consider the extent to which a “temporary shock” that increases an individual's donation to one cause by a particular amount displaces her gifts to other charitable causes. I use the 2001-2007 waves of the PSID/COPPS, the first data set of its kind, to identify this. Households that give more to one type of charity tend to give more to others. However, many of the correlations between the residuals after fixed-effects regressions are negative and significant, particularly for larger donors and for certain categories of charitable giving. Given plausible econometric assumptions, the negative correlations are strong evidence of expenditure substitution. Overall, these results suggest heterogeneous motivations for giving: small givers may be mainly driven by temporary shocks and personal appeals while larger givers may have concave multi-charity warm-glow preferences.

Consumers have shown a willingness to pay a premium for products labeled as "FT" and a preference for retailers that are seen to be more generous to their suppliers/employees. A FT product is essentially a bundle of a base product and a donation to the supplier (e.g., a coffee farmer). An altruistic rational consumer will only choose this bundle if doing so is less expensive than buying the base product and making a direct donation. For FT to be sustainable either in a competitive equilibrium or in a monopolistic environment this bundling must yield an efficiency. This efficiency is generated in the following context. A supplier's investment reduces the retailer's cost or boosts the final product's quality, but this investment is not immediately observable and cannot be enforced, hence there exists a moral hazard problem. In this environment, the altruism of the consumer can facilitate a more efficient contract: by paying the supplier more the retailer can both extract more consumer surplus and increase the level of contracted investment, while preserving the supplier's incentive compatibility constraint. We assess our model in the context of the coffee industry.