Validity and Reliability

Post date: Aug 26, 2012 4:45:48 PM

Two views about the relationship between validity and reliability.

1. Some people argue that reliability is a necessary but not sufficient component of validity. That is, if a measurement is valid, then it is also reliable. But just because it is reliability doesn't mean it is valid.

2. Others argue that the concepts are orthogonal to each other, as in the following table.

The graphic below portrays the same idea.