Scrapybara · lordspline · Jun 19, 2026 · Jun 19, 2026 · Jun 19, 2026
diff --git a/frontend/src/mocks/fixtures/api/experiments/experiment_frequentist_five_variants.json b/frontend/src/mocks/fixtures/api/experiments/experiment_frequentist_five_variants.json
@@ -1,6 +1,6 @@
 {
     "id": 20,
-    "name": "frequentist-five-variants",
+    "name": "frequentist-five-variants-custom-baseline",
     "description": null,
     "start_date": "2025-05-25T13:33:00Z",
     "end_date": null,
@@ -149,10 +149,17 @@
             "uuid": "fb633a4e-f3a9-429a-8b89-3f4e6967a71a"
         }
     ],
-    "primary_metrics_ordered_uuids": ["645b7e87-0e3b-4543-8e75-6234d5310e64", "9f7d52f5-175a-4210-a1a9-804d8aca19af"],
-    "secondary_metrics_ordered_uuids": ["a89f1069-8f38-44c7-955e-fd325c5370b2", "fb633a4e-f3a9-429a-8b89-3f4e6967a71a"],
+    "primary_metrics_ordered_uuids": [
+        "645b7e87-0e3b-4543-8e75-6234d5310e64",
+        "9f7d52f5-175a-4210-a1a9-804d8aca19af"
+    ],
+    "secondary_metrics_ordered_uuids": [
+        "a89f1069-8f38-44c7-955e-fd325c5370b2",
+        "fb633a4e-f3a9-429a-8b89-3f4e6967a71a"
+    ],
     "stats_config": {
-        "method": "frequentist"
+        "method": "frequentist",
+        "baseline_variant_key": "test-2"
     },
     "conclusion": null,
     "conclusion_comment": null

diff --git a/...s/fixtures/api/experiments/experiment_frequentist_five_variants_funnel_metric_result.json b/...s/fixtures/api/experiments/experiment_frequentist_five_variants_funnel_metric_result.json
@@ -1,9 +1,9 @@
 {
     "baseline": {
-        "key": "control",
-        "number_of_samples": 660,
-        "sum": 79.0,
-        "sum_squares": 79.0
+        "key": "test-2",
+        "number_of_samples": 678,
+        "sum": 85.0,
+        "sum_squares": 85.0
     },
     "cache_key": "cache_1fc548df0bb59cf67f3f74b10519d471",
     "cache_target_age": "2025-06-13T15:06:04.080661Z",
@@ -24,41 +24,53 @@
     "timezone": "UTC",
     "variant_results": [
         {
-            "confidence_interval": [-0.32664160293090333, 0.2427953597535722],
-            "key": "test-1",
+            "confidence_interval": [
+                -0.3194458396982118,
+                0.2289645562757519
+            ],
+            "key": "control",
             "method": "frequentist",
-            "number_of_samples": 654,
-            "p_value": 0.7727344039571313,
+            "number_of_samples": 660,
+            "p_value": 0.7462428557191743,
             "significant": false,
-            "sum": 75.0,
-            "sum_squares": 75.0
+            "sum": 79.0,
+            "sum_squares": 79.0
         },
         {
-            "confidence_interval": [-0.25342258906256815, 0.34819126835012276],
-            "key": "test-2",
+            "confidence_interval": [
+                -0.35199939978481265,
+                0.18146513103143994
+            ],
+            "key": "test-1",
             "method": "frequentist",
-            "number_of_samples": 678,
-            "p_value": 0.7573533369503214,
+            "number_of_samples": 654,
+            "p_value": 0.5306892004774055,
             "significant": false,
-            "sum": 85.0,
-            "sum_squares": 85.0
+            "sum": 75.0,
+            "sum_squares": 75.0
         },
         {
-            "confidence_interval": [-0.36928387310192495, 0.17097786932502407],
+            "confidence_interval": [
+                -0.39306123133072324,
+                0.1132454349974191
+            ],
             "key": "test-3",
             "method": "frequentist",
             "number_of_samples": 677,
-            "p_value": 0.4716076357323562,
+            "p_value": 0.2784838659844888,
             "significant": false,
             "sum": 73.0,
             "sum_squares": 73.0
         },
         {
-            "confidence_interval": [-0.24380565365903328, 0.375172144240116],
+            "confidence_interval": [
+                -0.2722028498636957,
+                0.30714495268907815
+            ],
             "key": "test-4",
             "method": "frequentist",
             "number_of_samples": 635,
-            "p_value": 0.6772180225948241,
+            "p_value": 0.905831712196401,
             "significant": false,
             "sum": 81.0,
             "sum_squares": 81.0

diff --git a/...cks/fixtures/api/experiments/experiment_frequentist_five_variants_mean_metric_result.json b/...cks/fixtures/api/experiments/experiment_frequentist_five_variants_mean_metric_result.json
@@ -1,9 +1,9 @@
 {
     "baseline": {
-        "key": "control",
-        "number_of_samples": 352,
-        "sum": 84.0,
-        "sum_squares": 84.0
+        "key": "test-2",
+        "number_of_samples": 370,
+        "sum": 70.0,
+        "sum_squares": 70.0
     },
     "cache_key": "cache_8928ab74ad19c9caa977c219e466cf0f",
     "cache_target_age": "2025-06-13T13:34:57.174521Z",
@@ -24,41 +24,53 @@
     "timezone": "UTC",
     "variant_results": [
         {
-            "confidence_interval": [0.07793147405845363, 0.7465883891354428],
+            "confidence_interval": [
+                -0.09497276429818707,
+                0.6177000370254597
+            ],
+            "key": "control",
+            "method": "frequentist",
+            "number_of_samples": 352,
+            "p_value": 0.15029635976120037,
+            "significant": false,
+            "sum": 84.0,
+            "sum_squares": 84.0
+        },
+        {
+            "confidence_interval": [
+                0.3245041084920392,
+                1.2382425371275347
+            ],
             "key": "test-1",
             "method": "frequentist",
             "number_of_samples": 362,
-            "p_value": 0.01572972589790078,
+            "p_value": 0.0008279139453490902,
             "significant": true,
             "sum": 122.0,
             "sum_squares": 122.0
         },
         {
-            "confidence_interval": [-0.4311719086701697, 0.01675749425575529],
-            "key": "test-2",
-            "method": "frequentist",
-            "number_of_samples": 370,
-            "p_value": 0.0697285633853224,
-            "significant": false,
-            "sum": 70.0,
-            "sum_squares": 70.0
-        },
-        {
-            "confidence_interval": [-0.16152208160745096, 0.40087708286721413],
+            "confidence_interval": [
+                0.031254975811512764,
+                0.7933859916865975
+            ],
             "key": "test-3",
             "method": "frequentist",
             "number_of_samples": 378,
-            "p_value": 0.40368585103186083,
-            "significant": false,
+            "p_value": 0.03398496530623474,
+            "significant": true,
             "sum": 101.0,
             "sum_squares": 101.0
         },
         {
-            "confidence_interval": [-0.30251617183973945, 0.23040298151568636],
+            "confidence_interval": [
+                -0.14099855656887744,
+                0.5727648733192194
+            ],
             "key": "test-4",
             "method": "frequentist",
             "number_of_samples": 313,
-            "p_value": 0.7905480103716265,
+            "p_value": 0.23533276612512544,
             "significant": false,
             "sum": 72.0,
             "sum_squares": 72.0

diff --git a/frontend/src/scenes/experiments/MetricsView/shared/ErrorChecklist.tsx b/frontend/src/scenes/experiments/MetricsView/shared/ErrorChecklist.tsx
@@ -40,14 +40,15 @@ function ChecklistItem({
     variants,
     getInsightType,
 }: ChecklistItemProps): JSX.Element {
+    const baselineVariantKey = experiment.stats_config?.baseline_variant_key ?? 'control'
     const failureText: Record<ResultErrorCode, string> = {
-        [ResultErrorCode.NO_CONTROL_VARIANT]: 'Events with the control variant not received',
+        [ResultErrorCode.NO_CONTROL_VARIANT]: `Events with the baseline variant (${baselineVariantKey}) not received`,
         [ResultErrorCode.NO_TEST_VARIANT]: 'Events with at least one test variant not received',
         [ResultErrorCode.NO_EXPOSURES]: 'Exposure events not received',
     }
 
     const successText: Record<ResultErrorCode, string> = {
-        [ResultErrorCode.NO_CONTROL_VARIANT]: 'Events with the control variant received',
+        [ResultErrorCode.NO_CONTROL_VARIANT]: `Events with the baseline variant (${baselineVariantKey}) received`,
         [ResultErrorCode.NO_TEST_VARIANT]: 'Events with at least one test variant received',
         [ResultErrorCode.NO_EXPOSURES]: 'Exposure events have been received',
     }
@@ -77,8 +78,10 @@ function ChecklistItem({
                     value: hasMissingExposure
                         ? variants.map((variant) => variant.key)
                         : errorCode === ResultErrorCode.NO_CONTROL_VARIANT
-                          ? ['control']
-                          : variants.slice(1).map((variant) => variant.key),
+                          ? [baselineVariantKey]
+                          : variants
+                                .filter((variant) => variant.key !== baselineVariantKey)
+                                .map((variant) => variant.key),
                     operator: 'exact',
                     type: 'event',
                 },

diff --git a/frontend/src/scenes/experiments/constants.ts b/frontend/src/scenes/experiments/constants.ts
@@ -63,17 +63,17 @@ export const CONCLUSION_DISPLAY_CONFIG: Record<
 > = {
     [ExperimentConclusion.Won]: {
         title: 'Won',
-        description: 'The test variant(s) outperformed the control with statistical significance.',
+        description: 'The test variant(s) outperformed the baseline with statistical significance.',
         color: 'bg-success',
     },
     [ExperimentConclusion.Lost]: {
         title: 'Lost',
-        description: 'The test variant(s) underperformed compared to the control with statistical significance.',
+        description: 'The test variant(s) underperformed compared to the baseline with statistical significance.',
         color: 'bg-danger',
     },
     [ExperimentConclusion.Inconclusive]: {
         title: 'Inconclusive',
-        description: 'No significant difference was detected between the variant(s) and the control.',
+        description: 'No significant difference was detected between the variant(s) and the baseline.',
         color: 'bg-warning',
     },
     [ExperimentConclusion.StoppedEarly]: {

diff --git a/frontend/src/scenes/experiments/legacy/metricsView/LegacyErrorChecklist.tsx b/frontend/src/scenes/experiments/legacy/metricsView/LegacyErrorChecklist.tsx
@@ -35,14 +35,15 @@ function ChecklistItem({
     getInsightType: (metric: any) => InsightType
     metric: any
 }): JSX.Element {
+    const baselineVariantKey = experiment.stats_config?.baseline_variant_key ?? 'control'
     const failureText: Record<ResultErrorCode, string> = {
-        [ResultErrorCode.NO_CONTROL_VARIANT]: 'Events with the control variant not received',
+        [ResultErrorCode.NO_CONTROL_VARIANT]: `Events with the baseline variant (${baselineVariantKey}) not received`,
         [ResultErrorCode.NO_TEST_VARIANT]: 'Events with at least one test variant not received',
         [ResultErrorCode.NO_EXPOSURES]: 'Exposure events not received',
     }
 
     const successText: Record<ResultErrorCode, string> = {
-        [ResultErrorCode.NO_CONTROL_VARIANT]: 'Events with the control variant received',
+        [ResultErrorCode.NO_CONTROL_VARIANT]: `Events with the baseline variant (${baselineVariantKey}) received`,
         [ResultErrorCode.NO_TEST_VARIANT]: 'Events with at least one test variant received',
         [ResultErrorCode.NO_EXPOSURES]: 'Exposure events have been received',
     }
@@ -72,8 +73,10 @@ function ChecklistItem({
                     value: hasMissingExposure
                         ? variants.map((variant: any) => variant.key)
                         : errorCode === ResultErrorCode.NO_CONTROL_VARIANT
-                          ? ['control']
-                          : variants.slice(1).map((variant: any) => variant.key),
+                          ? [baselineVariantKey]
+                          : variants
+                                .filter((variant: any) => variant.key !== baselineVariantKey)
+                                .map((variant: any) => variant.key),
                     operator: 'exact',
                     type: 'event',
                 },

diff --git a/frontend/src/scenes/experiments/stories/ExperimentFrequentistFiveVariants.stories.tsx b/frontend/src/scenes/experiments/stories/ExperimentFrequentistFiveVariants.stories.tsx
@@ -60,4 +60,4 @@ export default meta
 type Story = StoryObj<{}>
 
 // Small delay to ensure charts render completely
-export const ExperimentFrequentistFiveVariants: Story = { play: makeDelay(500) }
+export const ExperimentFrequentistFiveVariantsCustomBaseline: Story = { play: makeDelay(500) }
diff --git a/products/experiments/backend/hogql_queries/experiment_funnels_query_runner.py b/products/experiments/backend/hogql_queries/experiment_funnels_query_runner.py
@@ -51,6 +51,8 @@ def __init__(self, *args, **kwargs):
         self.variants = [variant["key"] for variant in self.feature_flag.variants]
         if self.experiment.holdout:
             self.variants.append(f"holdout-{self.experiment.holdout.id}")
+        stats_config = self.experiment.stats_config or {}
+        self.baseline_variant_key = stats_config.get("baseline_variant_key") or CONTROL_VARIANT_KEY
 
         self.prepared_funnels_query = self._prepare_funnel_query()
         self.funnels_query_runner = FunnelsQueryRunner(
@@ -144,7 +146,7 @@ def _prepare_funnel_query(self) -> FunnelsQuery:
     def _get_variants_with_base_stats(
         self, funnels_result: FunnelsQueryResponse
     ) -> tuple[ExperimentVariantFunnelsBaseStats, list[ExperimentVariantFunnelsBaseStats]]:
-        control_variant: Optional[ExperimentVariantFunnelsBaseStats] = None
+        baseline_variant: Optional[ExperimentVariantFunnelsBaseStats] = None
         test_variants = []
 
         for result in funnels_result.results:
@@ -158,8 +160,8 @@ def _get_variants_with_base_stats(
 
             breakdown_value = cast(list[str], first_step["breakdown_value"])[0]
 
-            if breakdown_value == CONTROL_VARIANT_KEY:
-                control_variant = ExperimentVariantFunnelsBaseStats(
+            if breakdown_value == self.baseline_variant_key:
+                baseline_variant = ExperimentVariantFunnelsBaseStats(
                     key=breakdown_value,
                     success_count=int(success),
                     failure_count=int(failure),
@@ -171,10 +173,10 @@ def _get_variants_with_base_stats(
                     )
                 )
 
-        if control_variant is None:
-            raise ValueError("Control variant not found in count results")
+        if baseline_variant is None:
+            raise ValueError(f"Baseline variant '{self.baseline_variant_key}' not found in count results")
 
-        return control_variant, test_variants
+        return baseline_variant, test_variants
 
     def _validate_event_variants(self, funnels_result: FunnelsQueryResponse):
         errors = {
@@ -193,15 +195,15 @@ def _validate_event_variants(self, funnels_result: FunnelsQueryResponse):
                 if event_dict.get("order") == 0:
                     eventsWithOrderZero.append(event_dict)
 
-        # Check if "control" is present
+        # Check if the baseline variant is present
         for event in eventsWithOrderZero:
             event_variant = event.get("breakdown_value", [None])[0]
-            if event_variant == "control":
+            if event_variant == self.baseline_variant_key:
                 errors[ExperimentNoResultsErrorKeys.NO_CONTROL_VARIANT] = False
                 break
 
         # Check if at least one of the test variants is present
-        test_variants = [variant for variant in self.variants if variant != "control"]
+        test_variants = [variant for variant in self.variants if variant != self.baseline_variant_key]
         for event in eventsWithOrderZero:
             event_variant = event.get("breakdown_value", [None])[0]
             if event_variant in test_variants:

diff --git a/products/experiments/backend/hogql_queries/experiment_query_runner.py b/products/experiments/backend/hogql_queries/experiment_query_runner.py
@@ -153,7 +153,7 @@ def __init__(
         ]
 
         stats_config = self.experiment.stats_config or {}
-        self.baseline_variant_key = stats_config.get("baseline_variant_key", CONTROL_VARIANT_KEY)
+        self.baseline_variant_key = stats_config.get("baseline_variant_key") or CONTROL_VARIANT_KEY
 
         self.date_range = get_experiment_date_range(self.experiment, self.team, self.override_end_date)
         self.date_range_query = QueryDateRange(