# POL222H1 Lecture Notes - Lecture 7: Confounding, Observational Study

## Document Summary

Lecture 7: observational study experiments we cannot control and randomly assign x world. Many interesting and important political science questions cannot be examined through. The feasible second-best solution is to use the actual observation of x,y and z in the real. Observational study: research design in which the researcher does not have control over the values of the independent variable. Lesson summary: basic logic of observational research, variety of observational research, classification by data type. Aggregate data: classification by unit of analysis. Divide observations according to values of x. Compare the average value of y across observations with different values of x. Relationship between x and y, controlling for z. Divide observations according to values of x and z. Compare the average value of y across different values of x among observations with the same value of z. Data types: individual survey data, study individuals randomly sampled from a population (e. g. economic voting in.