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title: View test assertion failure trends in performance tests
approved: 2026-4-08
max-toc-depth: 2
topictype: concept
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After a [performance test](/docs/collections/performance-testing/performance-test-configuration/) completes, you can analyze how your test assertions behaved under load. In the **Tests** tab, you can use the **Failure Trend** view to understand not just which requests failed, but when those failures occurred during the run. Use this information to identify why your API isn't behaving as expected under load and possible causes.

## View failed test assertions

You can view when requests and test assertions failed over the duration of the performance test.

On the **Summary** tab, you can click **Failure %** to view the top requests with failed test assertions that ran during the performance test. You can click **View failure trends** to open a time-based view of how failures occurred throughout the run.

![View top test assertion failures during performance test](https://assets.postman.com/postman-docs/v12/performance-test-top-failures-v12-01.png)

You can also open the **Tests** tab and click **Failure Trend** to analyze failures over time. In this view, you can see how test assertion failures evolve throughout the run, helping you identify when issues begin to appear.

In the table, you can view the requests that ran during the test and each failed test assertion. Next to each test assertion, you can view how often it failed relative to all requests in the run. Learn more about [debugging failed test assertions](#debug-failed-test-assertions).

## Debug failed test assertions

In the **Failure Trend** view, you can analyze how test assertion failures change over time during the performance test. This is useful for identifying when failures start, whether they correlate with increased traffic, and how they evolve during the test.

* Hover over a point on the graph to view the timestamp, number of failed requests, number of virtual users, and top failed requests.
* Click a point on the graph to filter the table to that point in time and inspect the failing requests and assertions. Click **Clear filter** to return to the default view.
* Click the **Filter by requests** dropdown list to filter the results by a specific request. Click **Reset** to return to the default view.

![View test assertion failures details](https://assets.postman.com/postman-docs/v12/performance-test-failures-details-v12-5.png)