# Lesson 9: Prewhitening; Intervention Analysis

**Overview**:

This week we'll look at two different topics - (1) prewhitening as an aid in interpreting a CCF, and (2) intervention analysis, which is the analysis of the effect of some sort of intervention to a time series process.

**Learning Objectives**:

After successfully completing this lesson, you should be able to:

- Know when and how to prewhiten in order to help identify which lags of x predict y
- Identify and interpret various patterns for intervention effects
- Estimate an intervention effect