Where these indirect effects may be significant, they are discussed. Several types of analytical techniques can be used in evaluations. The conduct of actual experiments is often the most rigorous analytical tool. Each group is then tracked to determine the differences in ultimate outcomes according to relevant measures such as wages, employment, and job retention. There are several significant challenges to conducting valid experiment based research, but it is one of the few means available to quantitatively analyze the net impact of programs.
Econometric analysis is a statistically based parallel to experimental analysis.
Instead of defining two groups and then tracking those groups over time, as in experimental analysis, groups are defined from existing data and a retrospective analysis is conducted. Econometric analysis can be used to assess program net impacts as well as program gross impacts. Sometimes it is not possible to perform experiments or econometric studies to determine the effect of a particular program. One approach that remains is to interview program participants to obtain their perceptions of what changed because of the program. Comparison of post-training data with benchmarks.