Test-retest reliability

Pre-requisites
Before reading this section, make sure you understand:
 * Correlation

Test-retest reliability
Test-retest reliability is the correlation between test scores taken at one time and another time.

An alternative, to help deal with potential practice effects, is alternate form reliability which is the correlation between two different forms of a test which are each completed at different times.

Tutorial exercise: Test-retest Reliability

 * leq01.sav (contains self-ratings of three constructed scales):
 * Time Management,
 * Emotional Control and
 * Self-Confidence collected approximately 1 month apart (Time 0 and Time 1).
 * Calculate the test-retest reliabilities for each scale.