validity

Experiments TIG Week: Biggest Complaints: Experiments have limited external validity, take too long, and cost too much by Laura Peck

Welcome to the final installment of the Design & Analysis of Experiments TIG-sponsored week of AEA365.  It’s Laura Peck of Abt Associates, here again to address some complaints about experiments. Experiments have limited external validity Experimental evaluation designs are often thought to trade internal validity (ability to claim cause-and-effect between program and impact) with external …

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Experiments TIG Week: Laura Peck on How I Learned to Love the Counterfactual Laura Peck

I’m Laura Peck, recovering professor and now full-time evaluator with Abt Associates.  For many years I taught graduate Research Methods and Program Evaluation courses. One part I enjoyed most was introducing students to the concepts of causality, internal validity and the counterfactual – summarized here as hot tips. Hot Tips: #1:  What is causality? Correlation …

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Memorial Week: Mel Mark on Remembering Donald T. Campbell (1916–1996), Pioneer in Evaluation Methodology

This is part of a series remembering and honoring evaluation pioneers leading up to Memorial Day in the USA on May 30. My name is Mel Mark, a former AEA President and former editor of the American Journal of Evaluation. Don Campbell used pithy phrases to communicate complex philosophical or methodological issues. My favorite was: …

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