What is an acceptable test-retest reliability coefficient?

Test-retest reliability has traditionally been defined by more lenient standards. Fleiss (1986) defined ICC values between 0.4 and 0.75 as good, and above 0.75 as excellent. Cicchetti (1994) defined 0.4 to 0.59 as fair, 0.60 to 0.74 as good, and above 0.75 as excellent.

What correlation coefficient is indicative of high test-retest reliability?

A test–retest correlation of 0.80 or higher can provide evidence of the test’s reliability (Cozby & Bates, 2012). Several factors could affect test–retest reliability, leading to unusually high or low correlations between scores across time. One such factor is the time interval between assessments.

How do you calculate test-retest reliability?

To measure test-retest reliability, you conduct the same test on the same group of people at two different points in time. Then you calculate the correlation between the two sets of results.

Is test-retest reliability a correlation?

Test-retest reliability is the most common measure of reliability. This correlation is known as the test-retest-reliability coefficient, or the coefficient of stability. The closer each respondent’s scores are on T1 and T2, the more reliable the test measure (and the higher the coefficient of stability will be).

What is the correlation coefficient of a retest test?

We can use a correlation calculator to find that the Pearson Correlation Coefficient between the two sets of scores is 0.836. Since this correlation is greater than 0.80, researchers could conclude that the test has good test-retest reliability.

How to calculate the reliability of a retest?

We calculate the test-retest reliability by using the Pearson Correlation Coefficient, which takes on a value between -1 and 1 where: 1 -1 indicates a perfectly negative linear correlation between two scores 2 0 indicates no linear correlation between two scores 3 1 indicates a perfectly positive linear correlation between two scores

What is the test-retest reliability coefficient for youth?

The test–retest reliability coefficient was .90 for youth aged 9 to 14 years ( N= 49) and .85 for youth aged 15 to 18 years ( N= 65) over a two week interval. Test–retest reliability of an instrument is computed by measuring subjects at two distinct occasions on the instrument and then computing the correlation.

How is reliability related to coefficient of stability?

The resulting correlation is the coefficient of stability – the more similar the scores, the higher the correlation. The test-retest reliability is heavily dependent upon the amount of time that passes between the two occasions.