JASP — SPSS, Rebuilt Free and Bayesian

Open-source statistics with a point-and-click interface, APA-ready output, and first-class Bayesian equivalents of every standard test — from the University of Amsterdam.

2026-07-17 1 MIN READ AI: ENTRY DRAFTED FROM DOCUMENTED CAPABILITIES — HANDS-ON VERIFICATION PENDING

Official Site https://jasp-stats.org
Category Stats
Pricing Free
Rating ★★★★☆ (4/5)

Overview

JASP gives SPSS refugees a familiar menu-driven interface, free, with output formatted for APA style — and adds accessible Bayesian versions of t-tests, ANOVA, and regression alongside their frequentist twins. Analyses update live as you tick options.

Why researchers use it

  • Zero-cost SPSS replacement — teaches and runs standard tests without licences
  • Bayesian by design — Bayes factors alongside p-values, same menus
  • Honest output — effect sizes and assumption checks encouraged by default

Getting started

  1. Download free for all platforms; open a CSV directly.
  2. Run a familiar test (t-test, ANOVA) and note the live-updating APA-style tables.
  3. Tick the Bayesian equivalent and learn to read Bayes factors with the built-in help.

The honest review

Strengths. The best on-ramp to Bayesian statistics in existence, and dramatically better default output hygiene than SPSS — students report results more completely with less prompting.

Limitations. Menu-driven means less flexible than R for unusual models; the analysis file format documents choices but is not a script — full pipeline reproducibility still favours code.

When NOT to use this If your analysis will ever need customisation beyond the menus — multilevel quirks, custom contrasts, simulation — invest in R now rather than hitting JASP’s ceiling mid-project.