Hostname: page-component-745bb68f8f-hvd4g Total loading time: 0 Render date: 2025-01-07T19:10:40.394Z Has data issue: false hasContentIssue false

Item Selection by the Constant Process

Published online by Cambridge University Press:  01 January 2025

George A. Ferguson*
Affiliation:
Department of Educational Research, University of Toronto

Abstract

This paper relates the constant process used in psychophysics to the problem of item selection. Each test item may be described in terms of a limen, which is an index of the point at which an item discriminates, and the standard deviation of the limen, which is an index of the “goodness” of discrimination. The method developed may be related not only to the description of items but also to the description of persons. Thus a person's ability may be described in terms of a limen and its standard deviation.

Type
Original Paper
Copyright
Copyright © 1942 The Psychometric Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

*

I am indebted to Godfrey H. Thomson of the University of Edinburgh for reading and criticising part of this paper, and to D. N. Lawley of the same University for assistance in the development of certain of the arguments contained herein.

References

Binet, A. and Simon, Th. Ann. Psychol., 1908, 14.Google Scholar
Thurstone, L. L. A method of scaling psychological and educational tests. J. educ. Psychol., 1925, 16, 433451.CrossRefGoogle Scholar
Thomson, G. H. A note on scaling tests. J. educ. Psychol., 1926, 17, 551553.CrossRefGoogle Scholar
Symonds, P. M. Choice of items for a test on the basis of difficulty. J. educ. Psychol., 1929, 20, 481493.CrossRefGoogle Scholar
Guilford, J. P. Psychometric methods, New York and London: McGraw-Hill Book Company, 1936.Google Scholar
Thomson, G. H. A direct deduction of the constant process used in the method of right and wrong cases. Psychol. Review, 1919, 26, 454464.CrossRefGoogle Scholar