diff --git a/README.md b/README.md
new file mode 100644
index 0000000..c035d94
--- /dev/null
+++ b/README.md
@@ -0,0 +1,8 @@
+# TrueSkill™
+
+Implementation of TrueSkill™ in Rust.
+
+## See
+* [mafredri/go-trueskill](https://github.com/mafredri/go-trueskill)
+* [JesseBuesking/trueskill](https://github.com/JesseBuesking/trueskill)
+* [sublee/trueskill](https://github.com/sublee/trueskill)
diff --git a/src/lib.rs b/src/lib.rs
index ac5f27e..cd23273 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -122,7 +122,7 @@ pub fn rate(rating_groups: &[&[Gaussian]]) {
 
     let mut trunc = Vec::new();
 
-    let epsilon = draw_margin(0.1, BETA, 2.0);
+    let epsilon = draw_margin(DRAW_PROBABILITY, BETA, 2.0);
 
     for i in 0..size - 1 {
         trunc.push(TruncateFactor::new(