Most papers that employ Differences-in-Differences estimation (DD) use many years of data and focus on serially correlated outcomes but ignore that the resulting standard errors are inconsistent. To illustrate the severity of this issue, we randomly generate placebo laws in state-level data

of an individual's beliefs about his or her own or a significant other's hopes, wishes, or aspirations for the individual) signify the absence of positive outcomes, which is associated with dejection-related emotions (e.g., disappointment, dissatisfaction, sadness). In contrast, discrepancies between

This paper uses a unique data set to measure peer effects among college roommates. Freshman year roommates and dormmates are randomly assigned at Dartmouth College. I find that peers have an impact on grade point average and on decisions to join social groups such as fraternities. Residential peer

outcomes and fail to realize that others may have just as many factors in their favor. Students listed the factors that they thought influenced their own chances of experiencing eight future events. When such lists were read by a second group of students, the amount of unrealistic optimism shown

of the work 254 HACKMAN AND OLDHAM setting and the device of the autonomous work group. Absent from the approach, for example, are explicit means for diagnosing a work system prior to change (to ascertain what "should" be changed, and how), or for evaluating in systematic terms the outcomes

determine the incentives of and the constraints on economic actors, and shape economic outcomes. As such, they are social decisions, chosen for their consequences. Because different groups and individuals typically benefit from different economic institutions, there is generally aconflict over these social

stigmatized group may protect the self-concept It is proposed that members of stigmatized groups may (a) attribute negative feedback to prejudice against their group, (b) compare their outcomes with those of the ingroup, rather than with the relatively advantaged outgroup, and (c) selectively devalue those

as studies of the relationship of interaction in small groups to outcomes. The analysis develops propositions concerning the kinds of discourse that are productive of different types of learning as well as propositions concerning how desirable kinds of interaction may be fostered. Whereas limited ex

in mental accounting activities. Three components of mental accounting receive the most attention. This first captures how outcomes are perceived and experienced, and how decisions are made and subsequently evaluated. The accounting system provides the inputs to be both ex ante and ex post cost

in safer neighborhoods that had lower poverty rates than those of the control group not offered vouchers. We find no significant overall effects of this intervention on adult economic self-sufficiency or physical health. Mental health benefits of the voucher offers for adults and for female youth were