ERIC Number: EJ1106509
Record Type: Journal
Publication Date: 2016
Abstractor: As Provided
Reference Count: 39
Estimating the Standard Error of the Impact Estimator in Individually Randomized Trials with Clustering
Weiss, Michael J.; Lockwood, J. R.; McCaffrey, Daniel F.
Journal of Research on Educational Effectiveness, v9 n3 p421-444 2016
In the "individually randomized group treatment" (IRGT) experimental design, individuals are first randomly assigned to a treatment arm or a control arm, but then within each arm, are grouped together (e.g., within classrooms/schools, through shared case managers, in group therapy sessions, through shared doctors, etc.) to receive services. In the common setting where the second-stage grouping is not experimentally controlled, we demonstrate that the standard error estimators for the estimated treatment effects from both random and fixed effects models are biased because parameters required to compute the standard errors are not identifiable from the data. We discuss implications for designing and analyzing IRGTs and provide suggestions for mitigating the bias.
Descriptors: Randomized Controlled Trials, Error of Measurement, Control Groups, Experimental Groups, Cluster Grouping, Sampling, Sample Size, Models, Experimenter Characteristics, Statistical Bias, Simulation, Research Methodology, Computation
Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Sponsor: Institute of Education Sciences (ED)
Authoring Institution: N/A
IES Funded: Yes
Grant or Contract Numbers: R305D140032