What is reliable test? What is the validity of a test? If a test is not valid, then reliability is moot. Most simply put, a test is reliable if it is consistent within itself and across time. Test reliablility refers to the degree to which a test is consistent and stable in measuring what it is intended to measure.

A measurement maybe valid but not reliable, or reliable but not valid. Reliability and validity are independent of each other. If theresults of the personality test claimed that a very shy person was in factoutgoing, the test would be invalid. What makes a test valid?Ī test is valid if it measures what it is supposed to measure. The scale is reliable because it consistently reports the same weight every day, but it is not valid because it adds 5lbs to your true weight. For example, if your scale is off by 5 lbs, it reads your weight every day with an excess of 5lbs. How can a test be reliable but not valid example?įor a test to be reliable, it also needs to be valid. It is not a valid measure of your weight. How can a test be valid but not reliable example?įor example, if your scale is off by 5 lbs, it reads your weight every day with an excess of 5lbs. The ACT is valid (and reliable) because it measures what a student learned in high school. A test is valid if it measures what it’s supposed to. Reliability implies consistency: if you take the ACT five times, you should get roughly the same results every time. Likewise, a measure can be valid but not reliable if it is measuring the right construct, but not doing so in a consistent manner. If you’re providing a personality test and get the same results from potential hires after testing them twice, you’ve got yourself a reliable test.Ī measure can be reliable but not valid, if it is measuring something very consistently but is consistently measuring the wrong construct. However, a test can be reliable without being valid. Can a valid test be unreliable?Īs you’d expect, a test cannot be valid unless it’s reliable. If there is a high correlation, this gives a good indication that your test is measuring what it intends to measure. To evaluate criterion validity, you calculate the correlation between the results of your measurement and the results of the criterion measurement. A valid measurement is generally reliable: if a test produces accurate results, they should be reproducible.

9 What is the difference between concurrent validity and predictive validity?Ī reliable measurement is not always valid: the results might be reproducible, but they’re not necessarily correct.

8 Can a test be reliable without being valid?.

5 How can a test be reliable but not valid example?.4 How can a test be valid but not reliable example?.

A reliable test is always valid