Experiments

Internal Validity

Measures the extent to which a casual relationship can be concluded from the study

External validity

Measures the extent to which the study results can be generalized beyond the study

Typical relationship between internal and external validity

Inverse

Increases in internal validty result in decrease in external validty, and vise versa

Longitudinal Study

investigate a variable of interest within a sample population over a period of time

Ethnographic Studies

Use observation and interview to qualitatively study people for their cultures, behaviors, norms, and values

A randomized controlled trial

randomly sorts subjects into treatment and control groups to test effect of independent variable

Cross Sectional Study

observational study that measures a variable in a population at one time point