diff --git a/src/common/telemetry/constants.ts b/src/common/telemetry/constants.ts
index 47e45888..e77a2568 100644
--- a/src/common/telemetry/constants.ts
+++ b/src/common/telemetry/constants.ts
@@ -65,6 +65,9 @@ export enum EventNames {
      * the timer is cancelled and this event never fires.
      * Properties:
      * - failureStage: string (which phase was in progress when the watchdog fired)
+     * Measures:
+     * - duration: total elapsed since activation
+     * - stageDuration: elapsed in the current stage
      */
     SETUP_HANG_DETECTED = 'SETUP.HANG_DETECTED',
     /**
@@ -103,12 +106,10 @@ export enum EventNames {
     ENV_SELECTION_RESULT = 'ENV_SELECTION.RESULT',
     /**
      * Telemetry event fired when applyInitialEnvironmentSelection returns.
-     * Duration measures the blocking time (excludes deferred global scope).
      * Properties:
-     * - globalScopeDeferred: boolean (true = global scope fired in background, false = awaited)
-     * - workspaceFolderCount: number (total workspace folders)
-     * - resolvedFolderCount: number (folders that resolved with a non-undefined env)
-     * - settingErrorCount: number (user-configured settings that could not be applied)
+     * - globalScopeDeferred: boolean (true = global scope fired in background)
+     * Measures:
+     * - duration, workspaceFolderCount, resolvedFolderCount, settingErrorCount
      */
     ENV_SELECTION_COMPLETED = 'ENV_SELECTION.COMPLETED',
     /**
@@ -381,7 +382,8 @@ export interface IEventNamePropertyMapping {
     /* __GDPR__
         "setup.hang_detected": {
             "failureStage": { "classification": "SystemMetaData", "purpose": "FeatureInsight", "owner": "StellaHuang95" },
-            "<duration>": { "classification": "SystemMetaData", "purpose": "FeatureInsight", "isMeasurement": true, "owner": "StellaHuang95" }
+            "<duration>": { "classification": "SystemMetaData", "purpose": "FeatureInsight", "isMeasurement": true, "owner": "eleanorjboyd" },
+            "<stageDuration>": { "classification": "SystemMetaData", "purpose": "FeatureInsight", "isMeasurement": true, "owner": "eleanorjboyd" }
         }
     */
     [EventNames.SETUP_HANG_DETECTED]: {
@@ -451,9 +453,6 @@ export interface IEventNamePropertyMapping {
     */
     [EventNames.ENV_SELECTION_COMPLETED]: {
         globalScopeDeferred: boolean;
-        workspaceFolderCount: number;
-        resolvedFolderCount: number;
-        settingErrorCount: number;
     };
 
     /* __GDPR__
diff --git a/src/extension.ts b/src/extension.ts
index f635874a..ec8a24cd 100644
--- a/src/extension.ts
+++ b/src/extension.ts
@@ -552,6 +552,7 @@ export async function activate(context: ExtensionContext): Promise<PythonEnviron
      */
     setImmediate(async () => {
         let failureStage = 'nativeFinder';
+        const stageWatch = new StopWatch();
         // Watchdog: fires if setup hasn't completed within 120s, indicating a likely hang
         const SETUP_HANG_TIMEOUT_MS = 120_000;
         let hangWatchdogActive = true;
@@ -568,7 +569,11 @@ export async function activate(context: ExtensionContext): Promise<PythonEnviron
             }
             hangWatchdogActive = false;
             traceError(`Setup appears hung during stage: ${failureStage}`);
-            sendTelemetryEvent(EventNames.SETUP_HANG_DETECTED, start.elapsedTime, { failureStage });
+            sendTelemetryEvent(
+                EventNames.SETUP_HANG_DETECTED,
+                { duration: start.elapsedTime, stageDuration: stageWatch.elapsedTime },
+                { failureStage },
+            );
         }, SETUP_HANG_TIMEOUT_MS);
         context.subscriptions.push({ dispose: clearHangWatchdog });
         try {
@@ -592,6 +597,7 @@ export async function activate(context: ExtensionContext): Promise<PythonEnviron
             sysPythonManager.resolve(sysMgr);
             // Each manager registers independently — one failure must not block the others.
             failureStage = 'managerRegistration';
+            stageWatch.reset();
             await Promise.all([
                 safeRegister(
                     'system',
@@ -611,14 +617,17 @@ export async function activate(context: ExtensionContext): Promise<PythonEnviron
             ]);
 
             failureStage = 'envSelection';
+            stageWatch.reset();
             await applyInitialEnvironmentSelection(envManagers, projectManager, nativeFinder, api, start.elapsedTime);
 
             // Register manager-agnostic terminal watcher for package-modifying commands
             failureStage = 'terminalWatcher';
+            stageWatch.reset();
             registerTerminalPackageWatcher(api, terminalActivation, outputChannel, context.subscriptions);
 
             // Register listener for interpreter settings changes for interpreter re-selection
             failureStage = 'settingsListener';
+            stageWatch.reset();
             context.subscriptions.push(
                 registerInterpreterSettingsChangeListener(envManagers, projectManager, nativeFinder, api),
             );
diff --git a/src/features/interpreterSelection.ts b/src/features/interpreterSelection.ts
index 24e36061..27f92bdf 100644
--- a/src/features/interpreterSelection.ts
+++ b/src/features/interpreterSelection.ts
@@ -395,13 +395,19 @@ export async function applyInitialEnvironmentSelection(
         await notifyUserOfSettingErrors(allErrors);
     }
 
-    // Duration measures blocking time only (excludes deferred global scope).
-    sendTelemetryEvent(EventNames.ENV_SELECTION_COMPLETED, selectionStopWatch.elapsedTime, {
-        globalScopeDeferred: workspaceFolderResolved,
-        workspaceFolderCount: folders.length,
-        resolvedFolderCount,
-        settingErrorCount: allErrors.length,
-    });
+    // Numeric values must go via the measures argument (properties are dropped).
+    sendTelemetryEvent(
+        EventNames.ENV_SELECTION_COMPLETED,
+        {
+            duration: selectionStopWatch.elapsedTime,
+            workspaceFolderCount: folders.length,
+            resolvedFolderCount,
+            settingErrorCount: allErrors.length,
+        },
+        {
+            globalScopeDeferred: workspaceFolderResolved,
+        },
+    );
 }
 
 /**