Contents
What is an acceptable Alpha?
There are different reports about the acceptable values of alpha, ranging from 0.70 to 0.95. 2, 21, 22. A low value of alpha could be due to a low number of questions, poor inter-relatedness between items or heterogeneous constructs.
What is an acceptable reliability coefficient?
A general accepted rule is that α of 0.6-0.7 indicates an acceptable level of reliability, and 0.8 or greater a very good level.
What is a good KR-20 score?
0.70
A KR-20 score above 0.70 is generally considered to represent a reasonable level of internal consistency reliability.
Which is better, KR20 or Cronbach’s Alpha?
If items are not binary (e.g., test questions where examinees may receive partial credit), KR20 is not appropriate and Cronbach’s alpha is the better choice. In psychology, I’ve rarely seen KR20 reported and Cronbach’s alpha is far, far more common.
What should the value of KR-20 be?
In very rare cases, typically with very small samples, values less than 0.0 can occur, which indicates an extremely unreliable measurement. A rule-of-thumb commonly applied in practice is that 0.7 is an acceptable value or 0.8 for longer tests of 50 items or more.
How is the Alpha of a Cronbach scale calculated?
Cronbach’s alpha is computed by correlating the score for each scale item with the total score for each observation (usually individual survey respondents or test takers), and then comparing that to the variance for all individual item scores: α = (k k – 1) (1 – ∑ i = 1 k σ y i 2 σ x 2)
How is the Alpha of a scale calculated?
Cronbach’s alpha is computed by correlating the score for each scale item with the total score for each observation (usually individual survey respondents or test takers), and then comparing that to the variance for all individual item scores: Alternatively, Cronbach’s alpha can also be defined as: