Reliability

Definition

The consistency of a measure or test over time or across different observers.

Example

 A questionnaire designed to measure self-esteem should yield similar results when administered to the same group of individuals on different occasions, assuming no real change in their self-esteem.

Why It Matters

Reliability matters because research needs to be consistent to be trusted. If a measure gives different results each time it's used — even when nothing has changed — it’s hard to know what to believe. Reliable tools help researchers collect dependable data, which makes the findings stronger and more useful.

Related Terms

• validity
• measurement