Question 1

What is the difference between reliability and validity?

Accepted Answer

Reliability refers to the consistency of a measurement, whether it produces similar results under similar conditions, while validity refers to whether it actually measures what it claims to measure.

Question 2

Can a test be reliable but not valid?

Accepted Answer

Yes. A consistently wrong measure can be reliable, producing the same inaccurate result every time, without actually being valid.

Question 3

Can a test be valid without being reliable?

Accepted Answer

No. Reliability is generally necessary but not sufficient for validity; an unreliable measure that produces inconsistent results cannot be considered valid.

Question 4

How can I check whether an assessment has documented reliability and validity?

Accepted Answer

Look for stated evidence from the assessment provider, such as test-retest reliability figures or validity studies, rather than assuming a professional appearance guarantees rigor.

Assessment Reliability and Validity: The Two Standards That Matter