---
title: "Operational Definitions — AP Psychology Definition & Exam Guide"
description: "An operational definition states exactly how a variable is measured in a study. It's the backbone of replication and shows up in AP Psych research-design FRQs."
canonical: "https://fiveable.me/ap-psych-revised/key-terms/operational-definitions"
type: "key-term"
subject: "AP Psychology"
---

# Operational Definitions — AP Psychology Definition & Exam Guide

## Definition

An operational definition describes how to measure a variable or define a term. It outlines the procedures used in research.

## Related Study Guides

- [1.3 Defining Psychological Science: The Experimental Method](/ap-psych-revised/unit-1/experimental-method/study-guide/2GX0dM8rra0uAIF9hydm)

## Review

### Related Terms

- [Validity](/ap-psych-revised/key-terms/validity): This refers to how well a test measures what it's supposed to measure - like checking if your dish tastes as it should according to the recipe.
- [Reliability](/ap-psych-revised/key-terms/reliability): This is about consistency of measurement - if you follow the same recipe again, will you get the same result?
- [Replication](/ap-psych-revised/key-terms/replication): This involves repeating an experiment using the same methods but different subjects and experimenters, to see if similar results are obtained - like someone else trying out your recipe.