| Type of reliability |
When |
How |
What |
| Internal consitency |
Assess a single dimension |
Correlate each individual item score with the total score. |
All the items on your test assess the same construct. |
| Interrater |
Find consistency in the rating of some outcome |
Examine the percentage of agreement between raters. |
The reliability coefficient for your test indicates a poor, moderate, or high degree of agreement between respondents. |
| Parallel |
Compare several different forms of a test to see if they are equivalent or reliable |
Correlate the scores from one form of the test with scores from a second form of the same test with the same content. |
Two forms of your test are equivalent to one other. |
| Test-retest |
Reliability over time |
Correlate the scores from time 1 with the scores of time 2. |
The test gives the same results even if the participants didn't all take it at the same time. |
