Child Development 133 (03, 04,
72, 73 & 74)
Research Methods in Human Development

Hembree            Spring, 2013


External and Ecological Validity

I. External Validity

A. Introduction

= ability to generalize your experimental results




B. Three types of generalization:

1. to the population of interest



2. to the environment of interest




3. to the time of interest





C. Threats to External Validity

1) threats based on methods





2) threats based on participants




  D. Replication

1. Exact replication






2. Conceptual replication




E. Ecological Validity






F. What can we do to improve external and ecological validity?





II. Discussion Questions





Send problems, comments or suggestions to:

California State University, Sacramento

College of Education

Department of Child Development

Updated: January 25, 2013

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