## HANDOUT 5.2: MEASURES OF INTERNAL CONSISTENCY

TERM

SIGNIFICANCE
Cronbach's Alpha
A measure of internal consistency. Generally used for measures where participants respond to questions on a scale (1 to 3, 1 to 4, 1 to 5, etc.). Alpha can range between 0 and 1. If a scale has an alpha above .60, it is usually considered to be internally consistent.
Kuder-Richardson Reliability
Like Cronbach's alpha, except that it is used for measures in which items only can be responded to in one of two ways (true/false or yes/no). Like alpha, can range from 0 to 1. An internally consistent measure would have a Kuder-Richardson reliability of at least .60
Split-Half Reliability (often based on correlating the "Odds" with the "Evens")
An internally consistent measure should have a split half reliability of at least .75
Median Inter-Item Correlation
An index of the degree to which individual items correlate with each other. A median inter-item correlation of .30 usually indicates a high degree of internal consistency.