diff --git a/docs/security_analysis/custom_taint_sources.md b/docs/security_analysis/custom_taint_sources.md
index e72d6089f..8c61e8383 100644
--- a/docs/security_analysis/custom_taint_sources.md
+++ b/docs/security_analysis/custom_taint_sources.md
@@ -53,7 +53,7 @@ class BadSqlTainter implements AfterExpressionAnalysisInterface
         array &$file_replacements = []
     ) {
         if ($expr instanceof PhpParser\Node\Expr\Variable
-            && $expr->name === '$bad_data'
+            && $expr->name === 'bad_data'
         ) {
             $expr_type = $statements_source->getNodeTypeProvider()->getType($expr);