It represents the degree of correlation between test items. When the tested items are highly correlated, Cronbach's α coefficient is higher, indicating that the internal consistency of the test is better; On the other hand, if the items are independent of each other, Cronbach's α coefficient is low, which indicates that the internal consistency of the test is poor.
Cronbach's alpha coefficient is usually used to determine the reliability of research tools, especially in the fields of experimental psychology, educational research and market research. Generally speaking, Cronbach's α coefficient value higher than 0.7 indicates that the internal consistency of the test is good, and lower than 0.6 indicates that there is a problem with the internal consistency of the test.