# Measuring Experiments

## Using Autocapture

Sidecar automatically tracks various web activities, letting you create simple and complex metrics in the Statsig console without writing code. Create a new metric in the Metrics tab on the Statsig console to get started. For a full list of automatically logged metrics, refer to [Autocapture on the Web](https://docs.statsig.com/webanalytics/autocapture).

## Using the tracking API

You can track events manually for actions Autocapture doesn't capture.
To track events to Statsig, call `StatsigSidecar.logEvent`, which accepts the same arguments as the Statsig JS SDK, as [Logging an event](https://docs.statsig.com/client/javascript-sdk#logging-an-event) documents. You can call this method before the init routine completes.

```js
// example order event
StatsigSidecar.logEvent('Order', null, {
  total: 54.66,
  units: 3,
  unitAvgCost: 18.22
});
```

## Per-assignment callback for outbound integrations

You can bind a callback that Sidecar invokes each time it activates an experiment assignment, including experiments that prerun scripts activate later.

*Define this method before the Sidecar client script.*

```js
window.statsigSidecarConfig = {
  onExperimentEvaluation: function (event) {
    /**
     * add your own callback routine here
     * ie; annotating 3rd party analytics tools with assignment info
     */
    window.dataLayer = window.dataLayer || [];
    window.dataLayer.push({
      event: "statsig_experiment_evaluation",
      experiment_name: event.experimentName,
      experiment_group_name: event.groupName,
    });
  }
}
```

The callback payload includes the following fields:

| Field | Description |
|---|---|
| `event.name` | Always `"experiment_evaluation"`. |
| `event.experiment` | The full Statsig experiment object. |
| `event.experimentName` | The Sidecar experiment name, or the Statsig experiment name as a fallback. |
| `event.groupName` | The assigned group or variant, or `null` if unavailable. |

## Post-experiment callback for one-time readiness hooks

You can bind `window.postExperimentCallback` to receive a callback after Sidecar finishes its initial run. This callback fires even when there are no experiments, but doesn't cover experiments that prerun scripts activate later.

```js
window.postExperimentCallback = function(statsigClient, experimentIds) {
  // One-time initialization hook after Sidecar finishes the initial run
}
```

### Disabling all logging

To disable all logging to Statsig (both autocapture events and experiment exposure logging), append the following query string parameter to the Sidecar script URL: `&autostart=0`. Disabling logging is useful for GDPR compliance. You can re-enable events later with `client.updateRuntimeOptions({disableLogging: false})`.