# PSPP for Beginners

## What are effect sizes?

Effect sizes address the important question of treatment impact. An example is drug doses, with some drugs being more potent than others. It's useful to have a statistic that captures the potency of our experimental treatment.

Technically speaking, what effect size statistics do is capture the magnitude of the difference between groups. This is expressed as a score, with larger scores representing bigger effects. This quantification of impact complements the decision of statistical significant testing (significantly different or not?) by expessing how strong the intervention is.

Unfortunately, PSPP does not offer built-in effect size calculations. This is not a a major problem though because effect sizes can be easily calculated from the descriptive or intermediate calculations that PSPP provides in the output. The following web pages in this group can do simple calculations to show the effect size.

Home | Start | Variables | Data | Descriptive | Relationship | Inferential | Effect size | Advanced | Video

This work is licensed under a Creative Commons Attribution 4.0 International License that allows sharing, adapting, and remixing.