Randomize groups, not individuals: a strategy for improving early childhood programs.

Until the past few years, our nation's approach to designing federal programs for preschool-age children lacked coherence and paid little attention to what had worked (and not worked) in the past. In this article, the authors propose that credible information useful for designing effective programs will require the ongoing, systematic development and evaluation of alternative approaches for the improvement of large-scale early childhood programs. The research should place greater reliance on experiments in which existing groups of individuals, such as intact classes or preschool agencies, are randomly assigned to implement competing early education programs or program components. Randomizing groups, rather than individual children, changes the research question from "What works?" to "What works better?" yielding more useful information than is currently available about which preschool approaches ought to be strongly embedded in our nation's social policy.

Research Designs for Assessing the USDA's Food Assistance and Nutrition Programs Outcomes, Part 2: Impact Evaluation of Demonstrations.

This is the second part of a 2-part article that summarizes a review of research designs for assessing the impact of the USDA's food assistance and nutrition programs on nutrition and health. The first part focused on the research designs for evaluating ongoing national programs. Here, the random experiment and 3 quasi-experimental designs that can be used to evaluate the impacts of demonstration projects are reviewed.

The measurement of SES in health research: current practice and steps toward a new approach.

The resurgence of social epidemiology has yet to induce corresponding research into basic measurement issues. This paper aims to motivate investigators to refocus attention on the measurement of socioeconomic status (SES). With a primarily American focus, we document striking paucity of basic research in SES, review the history of SES measurement, highlight the central limitations of current measurement approaches, sketch a new theoretical perspective, present new pilot results, and outline areas for future research. We argue (1) that lack of conceptual clarity and the bypassing of standard psychometric techniques have retarded SES measurement. And (2) social epidemiologists should revisit the measurement of SES and consider whether a richer, psychometrically induced, approach would be more useful. Our pilot study suggests a great deal of uniformity between existing SES measures and that a new approach may be worthy of pursuit.