1. Psychology 202b Advanced Psychological Statistics, II March 31, 2011

2. Path Analysis Path analysis: –Fundamental theorem –Vocabulary review –Examples

3. Path Analysis The fundamental theorem: “The correlation between two variables X and Z is equal to the sum of the product of all paths from each possible tracing between X and Z. The tracings include all possible routes between X and Z, with the exceptions that (1) the same variable is not entered twice per tracing and (2) a variable is not both entered and exited through an arrowhead.” (Keith, p. 215)

4. Path Analysis More generally, the same idea works when coefficients are unstandardized (in which case, the total path is no longer a correlation).

5. Some Vocabulary Exogenous variables are variables that only have paths leading away from them. Endogenous variables also have paths leading into them. Recursive models have no paths with bidirectional flow. A saturated recursive model is one in which all possible recursive paths are present.

6. Examples A saturated recursive model. A nonsaturated recursive model. The idea of overidentification and the problem of model fit.

7. Next time Making things easier with SEM.