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

# Response curves

> Learn how response curves help Provalytics estimate saturation, spend headroom, and budget opportunity.

## Overview

Response curves show how expected outcomes change as spend changes.

They help answer:

> If we spend more or less in this channel, what is likely to happen?

## Why response curves matter

Media channels do not scale in a straight line forever.

At low spend levels, adding budget may create strong incremental gains. At higher spend levels, the same additional dollar may produce less impact. This is called diminishing returns or saturation.

Response curves help Provalytics identify:

* Channels with room to grow
* Channels approaching saturation
* Channels that may need budget reductions
* Channels that should be protected by guardrails

## How response curves are used

Provalytics uses response curves in planning and optimization features such as:

* Budget Recommendations
* Scenario Planner
* Spend Headroom

These tools use modeled relationships between spend and incremental outcomes to estimate how budget changes may affect performance.

## How to interpret a response curve

A response curve is not a guarantee. It is a modeled estimate based on observed data, channel behavior, and historical performance.

Use it as a planning guide, not as a promise.

The most useful questions are:

* Is the channel still efficient at higher spend?
* Is the next dollar likely to perform above or below target?
* Is the recommendation within a spend range where we have enough historical evidence?
* Are there business reasons to override the pure efficiency recommendation?

## Related features

* [Budget Recommendations](/planning/budget-recommendations)
* [Scenario Planner](/planning/scenario-planner)
* [Spend Headroom](/using-provalytics/spend-headroom)