diff --git a/include/evalhyd/detail/probabilist/contingency.hpp b/include/evalhyd/detail/probabilist/contingency.hpp
index 1ec44d2d3afd7bd4c1ef0d7845de0b51eb9d7271..9db86ad09014f7052a2b8711542e13fdb25ec61b 100644
--- a/include/evalhyd/detail/probabilist/contingency.hpp
+++ b/include/evalhyd/detail/probabilist/contingency.hpp
@@ -216,7 +216,7 @@ namespace evalhyd
                     const xt::xtensor<double, 3>& ct_c
             )
             {
-                return ct_b / (ct_a + ct_b + ct_c);
+                return ct_a / (ct_a + ct_b + ct_c);
             }
         }