# Average session duration

Understand how each variant in your experiment affects user session duration.

> **Automatically tracked**
>
> The SDK automatically tracks the events that feed this widget.

This widget shows how long users stay engaged with your application when exposed to different experiment variants. It helps you understand how each variant impacts session duration and whether changes introduced by the experiment encourage deeper engagement or lead users to disengage sooner.

## Metrics

![Average session duration widget](/assets/reference/analytics/experiment/average-session-duration.png)

The chart includes:

1. **Average session duration**\
   The average duration of sessions for users in your experiment.
2. **Session duration per variant**\
   The average duration of sessions for users exposed to each experiment variant.

> **Question: What does the comparison over the last period mean?**
>
> It represents the growth or decline of the metric compared to the previous period.
>
> The *last period* refers to the date filter you selected. For example, if the filter is set to the **last 7 days**, the *last period* will be the **7 days immediately before that range**.

## Interpretation

Differences in session duration help you understand how changes in copy, layout, messaging, or interaction design affect user behavior. A variant that increases session duration may be encouraging exploration, clarity, or relevance. On the other hand, a decrease in duration can indicate added friction, distraction, or misalignment with user intent. However, longer sessions are not always better; they may indicate confusion or difficulty completing tasks.

We calculate this metric using the formula:

```math
Average \space session \space duration = \frac{total \space duration \space of \space sessions}{total \space sessions}
```

### What the number tells you

Here are some common insights you can get from this widget:

- A given variant with a higher average session duration often indicates stronger engagement or clearer communication of value.
- A variant that significantly reduces session duration may be interrupting user flow or failing to meet expectations.
- Session duration becomes more meaningful when analyzed together with conversion metrics, helping you distinguish between variants that are efficient versus those that are merely time-consuming.

## Explore

- [Events](/reference/event/overview#event-types): Learn how to track user events for analytics and personalization.
- [Audiences](/explanation/audience): Understand how to deliver content to specific groups of users.