> ## Documentation index
> Fetch the complete documentation index at: https://arize.com/llms.txt
> Ask it with GET https://arize.com/ask?q=<keywords or question>. Short keywords rank best.
> Use these to discover all available pages before exploring further.

# 07.09.2025: Baseline for experiment comparisons

> Available in Phoenix 11.4+

<Update label="07.09.2025">

## Baseline for Experiment Comparisons

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You can now set a **baseline run** when comparing multiple experiments. This is especially useful when one run represents a known-good output (e.g. a previous model version or a CI-approved run), and you want to evaluate changes relative to it.

For example, in an evaluation like `accuracy`, you can easily see where the value flipped from `correct → incorrect` or `incorrect → correct` between your baseline and the current comparison - helping you quickly spot regressions or improvements.

This feature makes it easier to isolate the impact of changes like a new prompt, model, or dataset.

</Update>