Coefficient Alpha
Formula
Coefficient alpha is a general formula for scale reliability based on internal consistency. It provides the lowest estimate of reliability that can be expected for an instrument.
The formula for coefficient alpha is as follows:
where
| αxx | = | Coefficient alpha |
| N | = | Number of items constituting the instrument |
| S2 | = | Variance of the summated scale scores (e.g., assume that you compute a total score for each participant by summing responses to the items that constitute the scale; the variance of this total score variable would be S2) |
| ∑S2i | = | The sum of the variances of the individual items that constitute this scale |
When Will Coefficient ...
Get A Step-by-Step Approach to Using SAS® for Univariate & Multivariate Statistics, Second Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
