Statistics

JASP

JASP is a free, open-source statistics application that runs classical and Bayesian analyses side by side in one live interface, built for students, researchers, and teachers who want readable output without writing R code.

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✓ Software download·Open Source·Updated October 30, 2026
DeveloperJASP
LicenseOpen Source
File size1.4 GB
Languageen-US
Downloads10

JASP: Classical and Bayesian Statistics in One Interface

JASP is a statistics package built for people who read results rather than write code. You open a spreadsheet, choose an analysis from a menu, and fill in the variables; the output updates the moment an option changes, so a t-test, an ANOVA, or a regression can be adjusted until the specification matches the research question. What sets JASP apart is that every common analysis ships in two forms, a classical version reporting p-values and effect sizes and a Bayesian counterpart reporting Bayes factors, credible intervals, and posterior plots. Both appear in the same window, which makes the two philosophies easy to compare. Files are saved as .jasp projects that carry the data and analyses together, and CSV, Excel, and SPSS files import directly.

JASP grew out of an academic concern with reproducibility, and the interface reflects it. Because analyses are stored as settings rather than pasted output, reopening a project restores exactly which variables, options, and priors produced each table, and colleagues can inspect the choices instead of trusting a screenshot. Assumption checks, effect sizes, and robustness options sit close to the main result rather than buried in a separate menu. The module system extends the core install with specialised procedures, so a meta-analysis or a structural equation model arrives without switching programs. Output can be exported to HTML, PDF, LaTeX, or copied into a word processor, and analysts who need heavy time-series work often move the data across to gretl.

Benefits of Using JASP

The practical gain of JASP is that it removes the argument about which statistics to report. A researcher can run a classical t-test and its Bayesian equivalent in adjacent panels, see whether both point the same way, and decide what the evidence supports before writing a sentence. Priors are exposed rather than hidden, so a sceptical reader can see the assumptions behind a Bayes factor and test how sensitive the conclusion is to changing them. Because JASP is free and open source, a lab, a seminar, or a whole department can standardise on it without licence negotiations, and students can install it on their own machines. The interface also lowers the cost of switching methods: the same dialog family covers t-tests, ANOVA, regression, contingency tables, and their Bayesian versions, so learning one analysis teaches you most of the layout for the next.

JASP features

Key capabilities and highlights.

Feature 1

Classical and Bayesian Side by Side

Every standard analysis has two entries in the menu, one reporting p-values, effect sizes, and confidence intervals, the other reporting Bayes factors, credible intervals, and posterior distributions. Running both takes seconds, so a results section can present the two perspectives without moving data between programs and reviewers can judge whether the conclusions agree.

Feature 2

Live-Updating Output Panels

Results redraw as soon as a variable, option, or prior changes. There is no compile step and no stale table left on screen from an earlier specification, which means exploratory comparison of model variants stays honest about what was actually run and no result is copied forward by accident.

Feature 3

Assumption Checks and Diagnostics

Normality tests, homogeneity checks, outlier flags, and collinearity diagnostics sit beside the main table rather than behind a separate command. When an assumption fails, JASP shows which alternatives the data allow, so switching to a non-parametric or robust version is one menu selection away.

Feature 4

Editable Spreadsheet Data View

Data sits in a grid where variable types and value labels are declared once and applied everywhere. Filters, computed columns, and recodes can be layered on top, and the .jasp project keeps the original values intact so any reported figure can be traced back to the observation behind it.

Feature 5

Module System for Specialised Methods

The core install covers the everyday tests, while optional modules add meta-analysis, summary-statistics work, network analysis, structural equation modeling, and mixed models. Each module appears as an ordinary menu entry and its results behave like any built-in analysis, so the interface stays familiar when the method is specialised.

Feature 6

Bayesian Priors You Can Inspect

Rather than one fixed default, JASP exposes the prior distribution behind each Bayesian test and offers alternatives together with sensitivity plots. A reader who disagrees with your assumptions can see exactly what was specified and how far the conclusion shifts when the prior is changed.

Feature 7

Publication-Ready Tables and Figures

Tables export to HTML, PDF, LaTeX, or a word processor, and figures are generated from the same results, so numbers and plots never drift apart. Styling stays consistent across analyses, which shortens the gap between finished output and a submittable manuscript. Copy-and-paste keeps captions and labels attached.

Feature 8

Transparent Workflow for Teaching

Because every analysis records its settings, an instructor can distribute a project file and have students reproduce each table exactly, then change a single option to see the effect. Effect sizes and assumption results are shown by default, which keeps the reasoning visible instead of hidden behind a decision rule.

Old versions

Browse historical releases and previous builds.

0.99.0.02026-10-21
0.98.1.02026-07-07
0.98.0.02026-07-01
0.97.1.02026-06-05
0.97.0.02026-05-13

Frequently asked questions

Common questions about JASP.

Is JASP free to use?

Yes. JASP is free and open-source software, so students, teachers, and research groups can install it and use every built-in analysis without a licence fee, and the source code is available for inspection and reuse.

Does JASP include Bayesian analyses as well as classical ones?

It does. Most standard procedures appear twice in the menu, once as a classical test reporting p-values and effect sizes and once as a Bayesian analysis reporting Bayes factors, credible intervals, and posterior plots, using the same loaded data.

Do I need to know R to use it?

No. Every analysis is driven through menus and option panels. Knowing R helps only if you want to understand the engine underneath or build your own module for a method the existing analyses do not cover.

Which data files can it open?

It opens its own .jasp project files and imports common formats such as CSV, Excel workbooks, and SPSS data files, so an existing dataset generally needs no conversion before you can start specifying analyses.

What is a .jasp file?

A .jasp file is the native project format. It holds the dataset together with every analysis you built from it, including the options and priors you chose, so reopening it restores the exact tables rather than a blank workspace.

Can I add statistical methods that are not included by default?

Yes. JASP is module-based, and additional modules covering areas such as meta-analysis, network analysis, structural equation modeling, and mixed models can be added and then used like any built-in menu entry.

Can results be moved into a paper or report?

Tables and figures can be exported to HTML, PDF, or LaTeX, or copied straight into a word processor. Because figures are generated from the same results as the tables, the numbers and the plots stay consistent through editing.

Is JASP a good choice for teaching statistics?

It suits teaching because outputs appear immediately as options change and effect sizes plus assumption checks are visible by default. Students can also be given a JASP project file to reproduce exactly, which makes a methods exercise verifiable rather than a matter of trust.

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JASP is a free, open-source statistics application that runs classical and Bayesian analyses side by side in one live interface, built for students, researchers, and teachers who want readable output without writing R code.