### Abstract

Transient errors are caused by variations in feelings, moods, and mental states over time. If these errors are present, coefficient alpha is an inflated estimate of reliability. A true-score model is presented that incorporates transient errors for test-retest data, and a reliability estimate is derived. This estimate, referred to as the test-retest alpha, is less than coefficient alpha if transient error is present and is less susceptible to effects due to item recall than a test-retest correlation. An assumption underlying the test-retest alpha is essential tau equivalency of items. A test-retest split-half coefficient is presented as an alternative to the test-retest alpha when this assumption is violated. The test-retest alpha is the mean of all possible test-retest split-half coefficients.

Original language | English (US) |
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Pages (from-to) | 88-101 |

Number of pages | 14 |

Journal | Psychological Methods |

Volume | 8 |

Issue number | 1 |

DOIs | |

State | Published - Mar 2003 |

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### ASJC Scopus subject areas

- Psychology(all)

### Cite this

*Psychological Methods*,

*8*(1), 88-101. https://doi.org/10.1037/1082-989X.8.1.88

**A Coefficient Alpha for Test-Retest Data.** / Green, Samuel B.

Research output: Contribution to journal › Article

*Psychological Methods*, vol. 8, no. 1, pp. 88-101. https://doi.org/10.1037/1082-989X.8.1.88

}

TY - JOUR

T1 - A Coefficient Alpha for Test-Retest Data

AU - Green, Samuel B.

PY - 2003/3

Y1 - 2003/3

N2 - Transient errors are caused by variations in feelings, moods, and mental states over time. If these errors are present, coefficient alpha is an inflated estimate of reliability. A true-score model is presented that incorporates transient errors for test-retest data, and a reliability estimate is derived. This estimate, referred to as the test-retest alpha, is less than coefficient alpha if transient error is present and is less susceptible to effects due to item recall than a test-retest correlation. An assumption underlying the test-retest alpha is essential tau equivalency of items. A test-retest split-half coefficient is presented as an alternative to the test-retest alpha when this assumption is violated. The test-retest alpha is the mean of all possible test-retest split-half coefficients.

AB - Transient errors are caused by variations in feelings, moods, and mental states over time. If these errors are present, coefficient alpha is an inflated estimate of reliability. A true-score model is presented that incorporates transient errors for test-retest data, and a reliability estimate is derived. This estimate, referred to as the test-retest alpha, is less than coefficient alpha if transient error is present and is less susceptible to effects due to item recall than a test-retest correlation. An assumption underlying the test-retest alpha is essential tau equivalency of items. A test-retest split-half coefficient is presented as an alternative to the test-retest alpha when this assumption is violated. The test-retest alpha is the mean of all possible test-retest split-half coefficients.

UR - http://www.scopus.com/inward/record.url?scp=0043280893&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0043280893&partnerID=8YFLogxK

U2 - 10.1037/1082-989X.8.1.88

DO - 10.1037/1082-989X.8.1.88

M3 - Article

VL - 8

SP - 88

EP - 101

JO - Psychological Methods

JF - Psychological Methods

SN - 1082-989X

IS - 1

ER -