There is an increasing need for evidence-based practices in a variety of fields, from education to development to medicine. Buttressing this evidence base are improvements in methods for causal inference – from advanced experimental designs to methods for observational studies. As the field of evidence-based practice has matured, however, it has become clear that there is a disconnect between these methods – which prioritize internal validity – and the needs of decision makers – which prioritize external validity. I begin by reviewing this problem and then propose how causal inference research might better incorporate these external validity concerns. This will include a review of methods for generalizing results from samples to populations and methods for exploring treatment effect heterogeneity. Much of the talk will focus on how to better design studies to meet both internal and external validity goals.
about the speaker
Elizabeth Tipton is an Associate Professor of Statistics, Faculty Fellow at the Institute for Policy Research, and Co-Director of the Statistics for Evidence-Based Policy and Practice (STEPP) Center at Northwestern University. Her research focuses on the design and analysis of field experiments, with a particular focus on issues of external validity and generalizability; meta-analysis, particularly of dependent effect sizes; and the use of (cluster) robust variance estimation. She is an Associate Editor at the Journal of Educational and Behavioral Statistics and is a member of the boards of the Society for Research on Educational Effectiveness and Blueprints for Healthy Youth. Her work has been funded by the Institute for Education Sciences, the National Science Foundation, the Spencer Foundation and the Raikes Foundation. In 2020, she received the Frederick Mosteller Award from the Campbell Collaboration for her contributions to meta-analysis, and prior to this she received Early Career Awards from the American Education Research Association, the Society for Research Synthesis Methods, and the American Psychological Association. She received a Ph.D. in Statistics from Northwestern in 2011.