diff --git a/benchmarking/src/benchmarks/BenchmarkSuite.js b/benchmarking/src/benchmarks/BenchmarkSuite.js
index db1fdd0..f0487d7 100644
--- a/benchmarking/src/benchmarks/BenchmarkSuite.js
+++ b/benchmarking/src/benchmarks/BenchmarkSuite.js
@@ -13,11 +13,13 @@ export class BenchmarkSuite {
 
   setBenchmarkType(benchmarktype) {
     this.benchmarktype = benchmarktype
+    this.onChange()
   }
 
   setCases(cases) {
     this.cases = new CasesIterator(cases)
     this.stats = this.cases.getInitialStats()
+    this.onChange()
   }
 
   addStat(name, val) {
diff --git a/benchmarking/src/components/runner.js b/benchmarking/src/components/runner.js
index 86cc909..3a96850 100644
--- a/benchmarking/src/components/runner.js
+++ b/benchmarking/src/components/runner.js
@@ -37,13 +37,16 @@ export class BenchmarkRunner extends Component {
     if (prevState !== this.state) {
       this.props.onStatsChange(this.suite.stats)
     }
+    if (prevProps.formState !== this.props.formState) {
+      this.initializeSuite()
+      this.suite.stop()
+    }
   }
 
   initializeSuite() {
     let data = dataSelector[this.props.formState.dataset]
     this.suite.setBenchmarkType(benchmarkTypeSelector(this.props.formState))
     this.suite.setCases(generateCases(data, this.props.formState))
-    this.suite.start()
   }
 
   stateIsOneOf(states) {
@@ -83,7 +86,14 @@ export class BenchmarkRunner extends Component {
           </button>
 
           {this.startButtonShown() && (
-            <button onClick={() => this.initializeSuite()}>start</button>
+            <button
+              onClick={() => {
+                this.initializeSuite()
+                this.suite.start()
+              }}
+            >
+              start
+            </button>
           )}
 
           {this.resumeButtonShown() && (