PADP 7120 Lecture Notes - Lecture 3: Internal Validity, Convenience Sampling, Unimodality

• School: University of Georgia
• Department: Public Administration and Policy
• Course: PADP 7120
• Professor: Anastasopoulos

Document Summary

Lecture 3 : observational studies & experiments & causality: research design, purpose > answer causal questions about whether x causes y, & if so, to what extent, two major types (1) experiments. Assessing (through measurement) causality through intervention via randomization of some treatment measuring causal effects. Key element > randomization of independent variable: allows for causal inferences about a treatment, randomly assigning treatments prevent subjects from selecting into groups eliminates selection bias. Other major pieces (1) treatment > something that is randomly manipulated & presented to subjects independent variable (2) outcome > some method of comparing the treatments dependent variable. 2: whether those assigned to the treatment actually comply with the researchers demand to take the treatment, ex. Assessing causality through observing relationships between phenomena. Identifies individuals & collects information as events unfold (2) retrospective study. Collect data after events have taken place (3) example illustrating differences.