JASP vs SPSS: Free Bayesian-Friendly Stats vs the Classic

JASP is the better choice if you want free, open-source software with Bayesian versions of the standard tests and tables formatted for APA reports. SPSS is the better choice if your course runs on SPSS syntax and .sav files, or if you need its breadth of procedures and data management.

For a lot of coursework both will give you the same answer to the same question. The real differences are in the Bayesian side, in what happens to your files, and in syntax. Facts were checked on jasp-stats.org and ibm.com in October 2026. This page is published by the team behind TRTT, which we mention at the end; JASP isn't our product.

Short answer

What JASP does better

Bayesian statistics as a first-class option. JASP's defining feature is that most standard analyses come in two versions: classical (p values, confidence intervals) and Bayesian (Bayes factors, posterior distributions). You can run both on the same data and compare. SPSS has had a Bayesian Statistics menu since version 25, but in JASP the Bayesian versions sit right next to every common test and run across most of its modules.

Breadth for free. JASP's 30-plus modules go well past the basics: structural equation modelling, meta-analysis (including Cochrane meta-analyses), machine learning, network analysis, mixed models, survival, time series, power analysis, equivalence tests and more. In SPSS, several of these areas require add-on modules or aren't there at all.

Live, report-ready output. Results update as you tick options, and tables follow APA style by default. You can copy a table straight into Word, copy it as LaTeX, or export the whole results page as HTML or PDF.

Open source and cross-platform. JASP runs on Windows, macOS, Linux and ChromeOS (Chromebooks from 2019 onward, with limited functionality on ARM models), with no licence to renew.

What SPSS still does better

Syntax and scripting. SPSS's command language, with Paste from every dialog, is the backbone of many courses and research labs. Existing .sps files run in SPSS; they don't run in JASP. JASP's syntax mode (since version 0.17) shows R code that controls its analyses, which is useful but a different language.

Data management. SPSS has a full toolkit for preparing data: recodes, computes, aggregation, merging files, restructuring, weights and custom tables. JASP is mainly an analysis program. In particular, it has no general Weight Cases setting; only some analyses, such as linear regression, accept a weights variable. For weighted survey data, that matters.

Round-tripping .sav files. SPSS reads and writes .sav natively. JASP opens .sav but can only export data as CSV or other text formats; a request for .sav export has been open since 2020.

Breadth inside the classic workflow. Custom tables, complex samples, decision trees and many specialist procedures are available in SPSS's add-on bundles, in the same menus and syntax.

Institutional standard. Many textbooks, handouts and supervisors assume SPSS. That's not a technical advantage, but it's often the deciding one.

Common coursework tests in each program

If you're moving between the two, this is where the usual analyses live. JASP groups them into modules shown as icons across the top of the window; SPSS 32 puts them in the Analyze menu.

In JASP, the Bayesian version of each test sits in the same module as the classical one.

.sav files and syntax

If your data arrive as .sav files, JASP opens them with their labels. If you only need to analyse and report, that's enough.

The friction starts when you need to send data back. JASP exports CSV, TSV or text, which loses value labels and missing-value definitions. If a supervisor or co-author expects an updated .sav, you'll need another tool for that step (SPSS, PSPP, jamovi via export, TRTT, or R with haven).

Syntax is a clean divide: JASP doesn't run SPSS syntax. If your course hands out .sps files, JASP means rebuilding each analysis by clicking.

Output for APA reports

This is where JASP shines for students. Its tables are already close to APA formatting, so copying one into a Word document usually needs little cleanup, and Bayesian results come with plots that are easy to include.

SPSS output is accurate but looks like SPSS: pivot tables that usually need editing, or retyping, before they fit an APA report. If your goal is a clean results chapter rather than SPSS output, JASP saves time.

One caution: APA-style formatting doesn't replace checking what each number means. Make sure you know which test, which tail and which correction the table reports, whichever program made it.

Where TRTT fits

If you need SPSS habits (menus, syntax, .sav files) but don't have SPSS, TRTT sits between the two. It's free in a desktop browser with no install and no account, and the calculations run on your own computer. Its Analyze menu mirrors SPSS 32, it opens and saves .sav files with labels, and it runs procedures, transformations and labels from .sps files.

It isn't a JASP replacement: TRTT has no Bayesian analyses, and its output looks like SPSS rather than APA. Syntax support is partial (no DO IF, IF, LOOP, TO ranges, AGGREGATE, MATCH FILES or logistic regression yet), the web version has no PDF export and isn't designed for phone screens, and it isn't open source. On iPhone and iPad there's an app that's free for data sets up to 100 cases.

For the jamovi side of the comparison, see jamovi vs SPSS, and for all three free desktop tools, JASP vs jamovi vs PSPP. The full list of free options is in free SPSS alternatives.

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FAQ

Is JASP better than SPSS?

For Bayesian analysis, APA-ready output and price, yes. For SPSS syntax, data management, weighted survey data and writing .sav files, SPSS is stronger. For standard coursework tests, both give the same results.

Can JASP open SPSS files?

Yes. JASP opens .sav, .zsav and .por files. It can't save data back to .sav; data export is CSV or text.

Does JASP use SPSS syntax?

No. JASP has an R syntax mode, but it doesn't run SPSS .sps files.

Is JASP really free?

Yes. JASP is free and open source (AGPLv3 for the program), developed at the University of Amsterdam, with no licence fee or time limit.

Does SPSS have Bayesian statistics?

Yes. SPSS added Bayesian procedures in version 25, under Analyze ▸ Bayesian Statistics. JASP offers Bayesian versions across a wider range of its analyses.

TRTT is an independent product. It is not affiliated with or endorsed by IBM. IBM and SPSS are trademarks of International Business Machines Corporation.