Double counting

Double Counting

Same action fires multiple times, inflating metrics.

Symptom

Report shows 100 visitors for a page, but manual count is 50.

Either:

1. Each visitor is counted twice (double counting)
2. Or there's a real increase you didn't expect

Common causes

Cause 1: Multiple tracking codes

Page has both AppMeasurement AND Web SDK:

<!-- WRONG - two libraries -->
<script src="appMeasurement.js"></script>
<script src="alloy.js"></script>
<!-- Both fire hits simultaneously -->

Fix: Remove one library

Cause 2: Page reloads

Page has code that reloads and fires again:

// WRONG - fires on load
sendEvent();

// Then page reloads → fires again
location.reload();

Fix: Only fire once per logical page load

Cause 3: Link click fires twice

Link has onclick handler that fires AND default behavior fires:

<!-- WRONG -->
<a href="/next" onclick="trackClick()">Link</a>
<!-- Both custom tracking and page view fire -->

Fix: Use preventDefault() in handler

document.getElementById('link').addEventListener('click', (e) => {
  e.preventDefault(); // stops default navigation
  trackClick(); // fires custom event
  window.location = '/next';
});

Cause 4: SPA page navigation

Single-page app fire event on route change, then navigation fires again:

router.on('navigate', () => sendEvent()); // fires
// And also...
sendEvent(); // fired somewhere else too

Fix: One place sends events, not multiple

How to find double counting

In AEP Debugger:

1. Load page
2. Watch Debugger for hits
3. Count: how many hit requests fire?
4. Should be 1 per page

If 2+ hits appear, you have double counting.

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