Reliability analysis : How to obtain Cronbach Alpha value in SPSS

Cronbach's alpha is a statistical measure used to assess the internal consistency, or reliability, of a multiple-item scale or survey questionnaire. It is also sometimes referred to as coefficient alpha. The coefficient alpha provides an estimate of the average correlation of items within a scale and thus provides a summary measure of the scale's reliability.
The formula for calculating Cronbach's alpha is based on the average inter-item correlation and the number of items in the scale. A higher alpha value indicates a higher degree of internal consistency, and values close to 1.0 indicate a high degree of reliability.
Cronbach's alpha is widely used in social sciences, education, and psychology research, where researchers are interested in evaluating the reliability of measures like attitudes, opinions, and personality traits.
It is important to note that high internal consistency does not guarantee that a scale is a valid measure of a construct, but it is an important requirement for a valid measure. It's also important to consider other factors such as the content validity, criterion-related validity, and construct validity of the measure.