What is rule of thumb for Cronbach Alpha?

The general rule of thumb is that a Cronbach’s alpha of . 70 and above is good, . 80 and above is better, and . 90 and above is best.

What is an acceptable Cronbach’s alpha score?

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 the minimum sample size for Cronbach Alpha?

For a single coefficient alpha test, the approach by assuming the Cronbach’s alpha coefficient equals to zero in the null hypothesis will yield a smaller sample size of less than 30 to achieve a minimum desired effect size of 0.7.

How do you know if Cronbach’s alpha is reliable?

Cronbach’s alpha coefficient is more reliable when calculated on a scale from twenty items or less. Major scales that measure a single construct may give the false impression of a great internal consistency when they do not possess. Also, You can not go so far Design Scales of UN Single article.

What is a good reliability coefficient?

A coefficient of 0 means no reliability and 1.0 means perfect reliability. Since all tests have some error, reliability coefficients never reach 1.0. Generally, if the reliability of a standardized test is above . 80, it is said to have very good reliability; if it is below .

What is considered a good reliability coefficient?

Between 0.9 and 0.8: good reliability. Between 0.8 and 0.7: acceptable reliability. Between 0.7 and 0.6: questionable reliability. Between 0.6 and 0.5: poor reliability.

Does sample size affect Cronbach’s alpha?

The calculation of Cronbach’s alpha does not depend on sample size. Instead, it is formed from the average correlation and the number of items included in the potential scale.

What is the minimum sample size for reliability test?

The RCSI sample size handbook: a rough guide Conroy R (2016) This study summarized that sample size of 30 can measure reliability using Cronbach’s alpha considering the scale items have strong correlations. Therefore, the minimum sample size required for this case study is approximately 68 samples per group.

What is a good sample size for test-retest?

Conclusions: When researchers plan to assess the test-retest reliability of patient-reported outcome measures for older people, they need to consider an adequate time interval of approximately 13 days and the sample size of about 5 times the number of items.