The phrase "evidence-based policy" is frequently used, but it's crucial that such claims are scrutinized and validated. When the data on social and behavioral interventions are presented, high-quality evidence must be clearly defined and the methodology behind such studies held to rigorous standards.

Both the Cochrane Collaboration focusing on healthcare and the international Campbell Collaboration concentrating on criminal justice, education, and social services were created to develop, maintain and improve detailed guidelines for producing high-quality systematic reviews. And both organizations emphasize randomized controlled trials to evaluate the effectiveness of various interventions.

As a springboard from the Campbell Collaboration initiative and supported by the Rockefeller Foundation, this special issue of The Annals includes a thorough review of randomized tests across a variety of studies. Exploring significant dimensions of place randomized trials (also called cluster randomized trials or group randomized trials), these papers shed light on recent efforts to enhance the quality of designing such trials as well as on results reporting.

The research topics included in this volume are diverse. Taken together, these papers offer important insight into the nuts and bolts of conducting randomized trials: the significance of place in trials; how such studies are initiated; the incentives and justifications needed by participants; how to overcome challenges of implementation; and where to find out what studies have already been conducted or are currently underway.

While providing far-reaching insight into the topic of randomized testing, these papers also identify new issues and key questions to be further addressed in future research. Scholars and policymakers alike will find this collection of rigorous research essential in understanding the implications of current evidence-based policies as well as a guidepost for designing and conducting new studies. "

*Major revision of a work that gives researchers the tools to select the right theory for their evaluation task. *Clearly lays out the goals of each theory, how it translates into practice, and the conditions under which it is best applicable. *Third edition has an increased focus on diversity/equity and is organized around theories rather than individual theorists. *Top editors and contributors are highly regarded, experienced evaluators.

ROBERT F. BORUCH AND ROBERT W. PEARSON During the 13th Century. a vigorous argument among Middle Eastern rabbis concerned how one ought to make a fair assessment of an olive crop value for tithing purposes. Should one consolidate the crop. systematically mix the olives. and then conscientiously draw a small random sample? Or. might one simply grab a handful of olives from the nearest basket and make an estimate of the crop's worth. The issue. of course. is one that research designers and research users confront often -- balancing the need for information against the resources that must be put into actually collecting the data -- in deciding how much effort is warranted to produce fair evidence. For the rabbis. who argued for twenty-five years over the matter. the issue can be resolved with a special rule. In this as in other cases. if the demand for information is biblical in origin -- if God is its source. then one ought to be considerably conscientious; a more scientific and more expensive endeavor is warranted. We may at times subscribe to this kind of rule of thumb in determining what quality of information is warranted under what conditions. But other rules and approaches are possible. And as medieval Jewish. Arabic. and Christian philosophy suggests. the alternatives need to be thought out and tested. Our interest is a bit more contemporary but has some spiritual kinship with early scholars' interest in empirical evidence.

How can you tell if a new program has been effective or not? Is there any way to predict how a group of individuals would have fared without the new program or service? Packed with rich and varied examples, Robert F. Boruch untangles the complexities of randomized field experiments so that researchers can better evaluate the impact of new programs. Beginning with an exploration of how to judge whether or not a program worked (and for how much of the time), Boruch explores the context of experiments; the standards used to judge the ethical propriety of randomized experiments; methods for studying populations; and sampling methods, including pilot tests and arrangements for random allocation. He also covers baseline measures, including when to measure costs; missing data registry; and analyses of quality assurance, including analyses that have to be engineered to suit the departures from the design. Randomized Experiments for Planning and Evaluation is thoughtfully written, providing researchers with a reliable guide for constructing their own randomized field experiments. Randomized Experiments for Planning and Evaluation is for all professionals and practitioners in evaluation/research methods, statistics, psychology, sociology, political science, social work, and public health who need to stay on the cutting edge.