> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fetchhive.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Build an experiment

> Create an experiment, choose a dataset, and prepare candidates

Create an experiment when you want to compare one or more candidates against the same dataset.

## How do I create an experiment? <a href="#create-experiment" id="create-experiment" />

Open **Experiments**.

Click **Add Experiment**.

Enter a name and optional description.

Choose a dataset if you already have one.

Click **Add Experiment**.

You can also create the experiment first and attach or change the dataset before running.

## What should I add before running? <a href="#before-running" id="before-running" />

Before you start a run, make sure the experiment has:

* a dataset version
* at least one active candidate
* input columns that match the prompt inputs you expect to use

For prompts, make sure the dataset input column names match the prompt variables where possible.

## How should I name experiments? <a href="#naming" id="naming" />

Use names that explain the comparison.

Good examples:

* `Support FAQ prompt model comparison`
* `Invoice extraction prompt regression`
* `Refund policy prompt v3 vs deployed`

Avoid generic names such as `Test` or `Experiment 1`.

## Editing an experiment <a href="#editing" id="editing" />

Open the experiment.

Use the dropdown in the breadcrumbs to edit the experiment name or description.

Use **Archive** from the same menu when you no longer need the experiment in the main list.

Archived experiments are hidden from the default experiment list.

## Reproducibility <a href="#reproducibility" id="reproducibility" />

Experiments are designed to be repeatable.

Dataset versions are immutable. Candidates are captured as snapshots. This means a past run still points to the dataset rows and candidate configuration used at the time.

If you change a prompt later, add it as a new candidate or start a new experiment so the comparison remains clear.

See also: [Datasets](./datasets), [Add candidates](./candidates), and [Run an experiment](./running-experiments)