Select Page

What is an acceptable level of reliability for a psychometric test?

Most psychological societies (e.g., British Psychological Society) and academics (e.g., Devellis, 1991) suggest that an acceptable level of reliability for psychometric tests is:

Ability/Aptitude Tests: .80
Personality Tests: .70

Acceptable and unacceptable levels of the Cronbach’s Alpha coefficient:

 

Alpha coefficient

 

implied reliability

 

 

below .60

 

unacceptable

 

between .60 and .65

 

undesirable

 

between .65 and .70

 

minimally acceptable

 

between .70 and .80

 

respectable

 

between .80 and .90

 

very good

 

much above .90

 

consider shortening the scale

 

(DeVellis, 1991, p.85)

Reference
DeVellis, R.F. (1991). Scale development. Newbury Park, NJ: Sage Publications.