---
title: Implement an Experiment
description: "Learn how to deploy an experiment by pulling configurations, logging events, testing, and launching."
product: general
lang: en
token_estimate: 1321
---
# Implement an Experiment

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Implementing an experiment means reading its parameters in your code with `getExperiment`, logging the events your scorecard metrics use, and testing each variant in a non-production environment before you start it. Statsig generates the assignment code and runs the analysis on exposures and events; your code supplies the exposures and events. Use this page after you create the experiment in the console. To check a feature gate rather than read experiment parameters, follow the [feature gate SDK guide](https://docs.statsig.com/guides/check-gate) instead.

To deploy an experiment:

1. Pull the experiment configuration in your application.
2. Log the events you want in your experiment results.
3. Test the experiment in development or another lower environment.
4. Start the experiment.

## Pull experiment configurations from Statsig

The following snippet experiments on a product demo flow, where you might want to improve conversion through the funnel to demo completion. For full implementation details, go to the [SDK documentation](https://docs.statsig.com/sdks/getting-started) for your language, or work through the guide for [your first A/B test](https://docs.statsig.com/guides/abn-tests).

```javascript
const user = { userID: loggedInUserID };
const demoConfiguration = statsig.getExperiment(user, "demo_experience");

// use parameters to control the experience
if (demoConfiguration.get("show_banner", false)) {
  showBanner();
}

const title = demoConfiguration.get("title", "Start Demo");
banner.setTitle(title);
```

To get a starter snippet for your experiment, click **View Code Snippets** (the code icon next to **Start**) or **Code Snippet** in the _Groups and Parameters_ section of the _Setup_ tab. In the _Code_ dialog, choose your SDK from **SDK Type**.

![Experiment code snippet button](https://docs.statsig.com/images/experiments/code-snippet-button.png)

## Log events for your scorecard

To get results for the events and metrics you care about, instrument the experience with event logging. You can also set up an event integration or a data warehouse import to send events to Statsig's stats engine. With the Statsig SDKs, your code might look like this:

```javascript

statsig.logEvent(user, "demo_started");
...
statsig.logEvent(user, "demo_completed");
```

A few events let you measure how users move through a funnel in your product and experiment on those flows to increase conversion.

## Test in a lower environment

After you start an experiment, you can't edit the groups without restarting it, because Statsig is already allocating users to each group. Test each experiment in a lower environment before you start it. Testing in a lower environment together with [overrides](https://docs.statsig.com/experiments/setup/overrides) lets you set your own experiment group and test each variant.

To enable the experiment in lower environments:

1. On the experiment's _Setup_ tab, click **Test**, then **Enable for Environments**.
2. In the _Enable Experiment in Lower Environments_ dialog, select each environment to test in, for example **Development** or **Staging**. These environments should match your [SDK environment setup](https://docs.statsig.com/guides/using-environments#configuring-environments).
3. Click **Save**.

![Experiment test button interface](https://docs.statsig.com/images/experiments/experiment_test_button.png)

The experiment status changes from _Not Started_ to _Testing_. Refresh the page if the status doesn't update. To stop testing, clear every environment in the same dialog and click **Save**; the status returns to _Not Started_.

The **Test** menu also includes **Override IDs**, which opens the [overrides](https://docs.statsig.com/experiments/setup/overrides) dialog, and **View Exposures**, which opens the exposure stream on the _Diagnostics_ tab.

![Lower environment results showing cumulative exposures and metrics](https://docs.statsig.com/images/experiments/lower_environment_results.png)

In the results section, you can track cumulative exposures and metric results collected from lower environments. Statsig displays results in aggregate across all lower environments and doesn't distinguish between individual environments. Statsig retains metric data and exposure data even when you repeatedly disable and re-enable the experiment for the lower environment.

When you need to re-test the experiment end to end, resalt it to reshuffle users into new groups. While the experiment is in _Testing_, click the **⋯** menu next to **Start**, choose **Resalt**, then click **Confirm**.

![Lower environment resalt option](https://docs.statsig.com/images/experiments/lower_environment_resalt.png)

## Start the experiment

**Start** stays disabled until the setup is complete, for example until the experiment has at least one primary metric and at least one parameter in _Groups and Parameters_. Hover over **Start** to see which setup items are missing. After the setup is complete and you've tested the experiment in a lower environment, click **Start**. Your experiment is immediately live in production.