Efficiency of Multiple-Choice Tests as a Function of Spread of Item Difficulties  

Oleh:

Cronbach, Lee J. ; Warrington, Willard G.

Jenis: Article from Journal - e-Journal
Dalam koleksi: Psychometrika: A Journal of Quantitative Psychology vol. 17 no. 2 (Jun. 1952), page 127-147.
Topik: Multiple-Choice Tests; Function of Spread; Item Difficulties
Fulltext: Efficiency of Multiple-Choice Tests as a Function of Spread of Item Difficulties.pdf (937.21KB)

Isi artikel

The validity of a univocal multiple-choice test is determined for varying distributions of item difficulty and varying degrees of item precision. Validity is a function ofs d 2 +s v 2 , wheres d measures item unreliability ands v measures the spread of item difficulties. When this variance is very small, validity is high for one optimum cutting score, but the test gives relatively little valid information for other cutting scores. As this variance increases, eta increases up to a certain point, and then begins to decrease. Screening validity at the optimum cutting score declines as this variance increases, but the test becomes much more flexible, maintaining the same validity for a wide range of cutting scores. For items of the type ordinarily used in psychological tests, the test with uniform item difficulty gives greater over-all validity, and superior validity for most cutting scores, compared to a test with a range of item difficulties. When a multiple-choice test is intended to reject the poorestF per cent of the men tested, items should on the average be located at or above the threshold for men whose true ability is at theFth percentile.

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