Cronbach's Alpha is a measure of internal consistency/reliability. It is commonly used to determine the reliability of a scale comprised of multiple Likert questions in a survey/questionnaire. Many different thresholds are used to determine an appropriate reliability value, in the Table below you can see a selection of values from Cohen et al., (2018).
|0.90 or more||Very highly reliable|
|0.60 or less||Unacceptably low reliability|
Values from Page 744; Cohen, L., Manion, M., & Morrison, M. (2018) Research Methods in Education (8th ed.). Routledge.
Click Analyze > Scale > Reliability Analysis
Within the 'Reliability Analysis' window, select all of the variables you wish to analyse and move them to the 'Items' Box. Ensure that the model says 'Alpha', this is the default option. Then click OK.
SPSS will generate two tables, for this test we only need one table the Reliability Statistics
This table shows the specific test result being Cronbach's Alpha (α) and the number of items (N) that comprise the scale.