Bayesian A/B testing calculations for C++

Based on this post by Evan Miller

Also available in C and Rust

Add the header to your project (supports C++11 and greater).

There is also support for CMake and FetchContent:

include(FetchContent)

FetchContent_Declare(bayestest GIT_REPOSITORY https://github.com/ankane/bayestest-cpp.git GIT_TAG v0.2.0)
FetchContent_MakeAvailable(bayestest)

target_link_libraries(app PRIVATE bayestest::bayestest)

Include the header

#include "bayestest.hpp"

• Binary outcomes, like conversion rate
• Count data, like number of sales per salesperson

bayestest::BinaryTest test;
test.add(participants_a, conversions_a);
test.add(participants_b, conversions_b);
std::vector<double> probabilities = test.probabilities();

Supports up to 4 variants

bayestest::CountTest test;
test.add(events_a, exposure_a);
test.add(events_b, exposure_b);
std::vector<double> probabilities = test.probabilities();

Supports up to 3 variants

View the changelog

Everyone is encouraged to help improve this project. Here are a few ways you can help:

• Report bugs
• Fix bugs and submit pull requests
• Write, clarify, or fix documentation
• Suggest or add new features

To get started with development:

git clone https://github.com/ankane/bayestest-cpp.git
cd bayestest-cpp
cmake -S . -B build
cmake --build build
build/test