David Greenberg

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Despite generation upon generation of scaling, computer chips have until now remained essentially 2-dimensional. Improvements in on-chip wire delay and in the maximum number of I/O per chip have not been able to keep up with transistor performance growth; it has become steadily harder to hide the discrepancy. 3D chip technologies come in a number of(More)
Evaluations of government-funded training programs often combine results from similar operations in multiple sites. Findings inevitably vary. It is common to relate site-to-site variations in outcomes to variations in program design, participant characteristics, and the local environment. Frequently, such connections are constructed in a narrative synthesis(More)
To date, most evaluations of welfare-related employment and training (WRET) programs have focused on the difference between outcomes in a single site for people who receive the program's "treatment" and those in a control group who do not. This paper argues that progress in determining what makes programs effective requires greater emphasis on planning for(More)
This paper uses meta-analysis to investigate whether random assignment (or experimental) evaluations of voluntary government-funded training programs for the disadvantaged have produced different conclusions than nonexperimental evaluations. Information includes several hundred estimates from 31 evaluations of 15 programs that operated between 1964 and(More)
BACKGROUND This article describes eight flaws that occur in impact evaluations. METHOD The eight flaws are grouped into four categories on how they affect impact estimates: statistical imprecision; biases; failure of impact estimates to measure effects of the planned treatment; and flaws that result from weakening an evaluation design. Each flaw is(More)
Data from 76 experimental welfare-to-work programs conducted in the United States between 1983 and 1998 are used to investigate whether the impacts of such programs on employment had been improving over time and whether specific program features influencing such changes can be identified. Over the period, an increasing percentage of control group members(More)
Anthony E. Boardman, David H. Greenberg, Aidan R. Vining, David L. Weimer 1 Faculty of Commerce and Business Administration, 2053 Main Mall, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z2 (Tel.: 604 /822-8474, Fax: 604 /822-8477, e-mail: Anthony.Boardman@commerce.ubc.ca) 2 Department of Economics, 1000 Hilltop Circle, University(More)
BACKGROUND Impact evaluations draw their data from two sources, namely, surveys conducted for the evaluation or administrative data collected for other purposes. Both types of data have been used in impact evaluations of social programs. OBJECTIVE This study analyzes the causes of differences in impact estimates when survey data and administrative data(More)
This paper represents an initial attempt to view the role that social experiments, in general, and the income maintenance experiments and the wor Wwelfare demonstrations, in particular, have played in the policy process through the lens provided by the knowledge utilization literature. In addition to suggesting that the decision to conduct a social(More)