### Abstract

Cronbach's alpha coefficient is an index of reliability for the total score of a set of measurements. The alpha takes a value of 1.0 when the total score variance is perfectly attributable to the common factors running through the test items. In this research, a method of estimating Cronbach's coefficient alpha is proposed for the case where the parameters of dichotomous item response model arc known and the ability distribution of subjects is given. In addition, the case of polytomous response model where the item parameters are estimated by graded response model (Samejima, 1969) is also considered, and a method of estimating the alpha coefficient is proposed for that case.

Original language | English |
---|---|

Pages (from-to) | 227-233 |

Number of pages | 7 |

Journal | Shinrigaku Kenkyu |

Volume | 73 |

Issue number | 3 |

Publication status | Published - 2002 |

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### Keywords

- Cronbach's alpha coefficient
- Graded response model
- Item response theory
- Reliability

### ASJC Scopus subject areas

- Psychology(all)

### Cite this

*Shinrigaku Kenkyu*,

*73*(3), 227-233.

**Estimation of Cronbach's alpha coefficient in the context of item response theory.** / Shojima, Kojiro; Toyoda, Hideki.

Research output: Contribution to journal › Article

*Shinrigaku Kenkyu*, vol. 73, no. 3, pp. 227-233.

}

TY - JOUR

T1 - Estimation of Cronbach's alpha coefficient in the context of item response theory

AU - Shojima, Kojiro

AU - Toyoda, Hideki

PY - 2002

Y1 - 2002

N2 - Cronbach's alpha coefficient is an index of reliability for the total score of a set of measurements. The alpha takes a value of 1.0 when the total score variance is perfectly attributable to the common factors running through the test items. In this research, a method of estimating Cronbach's coefficient alpha is proposed for the case where the parameters of dichotomous item response model arc known and the ability distribution of subjects is given. In addition, the case of polytomous response model where the item parameters are estimated by graded response model (Samejima, 1969) is also considered, and a method of estimating the alpha coefficient is proposed for that case.

AB - Cronbach's alpha coefficient is an index of reliability for the total score of a set of measurements. The alpha takes a value of 1.0 when the total score variance is perfectly attributable to the common factors running through the test items. In this research, a method of estimating Cronbach's coefficient alpha is proposed for the case where the parameters of dichotomous item response model arc known and the ability distribution of subjects is given. In addition, the case of polytomous response model where the item parameters are estimated by graded response model (Samejima, 1969) is also considered, and a method of estimating the alpha coefficient is proposed for that case.

KW - Cronbach's alpha coefficient

KW - Graded response model

KW - Item response theory

KW - Reliability

UR - http://www.scopus.com/inward/record.url?scp=0036674762&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036674762&partnerID=8YFLogxK

M3 - Article

C2 - 12436881

AN - SCOPUS:0036674762

VL - 73

SP - 227

EP - 233

JO - Shinrigaku Kenkyu

JF - Shinrigaku Kenkyu

SN - 0021-5236

IS - 3

ER -