# Spearman-Brown formula

## Spearman-Brown formula

[¦spir·mən ′brau̇n ‚fȯr·myə·lə]
(statistics)
A formula to estimate the reliability of a test n times as long as one for which reliability is known; the tests must be comparable in all aspects other than size.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The reliability was calculated by using Spearman-Brown formula: Reliability = 2r/1+r
Other tools we used to test internal consistency of the scale were Spearman-Brown formula and split-half reliability.
Referring to the technical characteristics of the tools, the reliability was analyzed through the internal coherence which presented the answers of the different samples, calculating the correlation between the two halves of the questionnaire using the Spearman-Brown formula.
Then, the reliability of the slope was estimated as the correlation between individual slopes from the two parallel processes with a correction by the Spearman-Brown formula. (Contains 15 tables.)
The reliability was done using Pearson Product Moment Correlation that was .67 and the final Spearman-Brown formula yielded 0.80 which showed the instrument was reliable.
The correlation coefficient was corrected by the use of Spearman-Brown formula. The Pearson Product Moment Correlation was .67 and the final Spearman Brown formula yielded 0.80.
Stated another way, an empirical study, which demonstrates that repeated test administrations results in increased test validity, has the potential to meet the requirements of the courts, whereas a mathematical demonstration using the Spearman-Brown formula to show that reliability and potential validity should increase seems much less likely to be accepted by the courts.
Although the Spearman-Brown formula prophesizes what will happen as a result of using repeated measures, we believe that demonstrating empirically the potential applicability of using a repeated-measures design to demonstrate a test's job-relatedness is value-added.
The relationship is captured in the well-known Spearman-Brown formula (Gulliksen, 1987, p.
The Spearman-Brown formula, applied to phi correlations calculated for each pair of item scores, estimated full-scale reliabilities of 0.87 for the Negative Reinforcement scale and 0.79 for the Sensitivity to Criticism and Failure scale (Anastasi, 1988).
Reliability coefficients, calculated using the Spearman-Brown formula, ranged from .80 for the U.S.
Split-half reliabilities using the Spearman-Brown formula were r - .62 for I, .66 for P, and .64 for C.
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