The continued search for nonarbitrary metrics in psychology.

H. Blanton and J. Jaccard examined the arbitrariness of metrics in the context of 2 current issues: (a) the measurement of racial prejudice and (b) the establishment of clinically significant change. According to Blanton and Jaccard, although research findings are not undermined by arbitrary metrics, individual scores and score changes may not be meaningfully interpreted. The author believes that their points are mostly valid and that their examples were appropriate. However, Blanton and Jaccard's article does not lead directly to solutions, nor did it adequately describe the scope of the metric problem. This article has 2 major goals. First, some prerequisites for nonarbitrary metrics are presented and related to Blanton and Jaccard's issues. Second, the impact of arbitrary metrics on psychological research findings are described. In contrast to Blanton and Jaccard (2006), research findings suggest that metrics have direct impact on statistics for group comparisons and trend analysis.

[1]  E. Muraki.  A Generalized Partial Credit Model: Application of an EM Algorithm , 1992 .

[2]  S. Embretson,et al.  Item response theory for psychologists , 2000 .

[3]  Scott E. Maxwell,et al.  Measurement and Statistics: An Examination of Construct Validity. , 1985 .

[4]  Susan E. Embretson,et al.  Item Response Theory Models and Spurious Interaction Effects in Factorial ANOVA Designs , 1996 .

[5]  James Jaccard,et al.  Arbitrary metrics in psychology. , 2006, The American psychologist.

[6]  I. W. Molenaar,et al.  Rasch models: foundations, recent developments and applications , 1995 .

[7]  Mark L. Davison,et al.  Parametric statistics and levels of measurement : factorial designs and multiple regression , 1990 .

[8]  A. S. Otis.  A criticism of the Yerkes-Bridges Point Scale, with alternative suggestions. , 1917 .

[9]  L. L. Thurstone,et al.  A method of scaling psychological and educational tests. , 1925 .

[10]  P. Boeck,et al.  Explanatory item response models : a generalized linear and nonlinear approach , 2004 .

[11]  Frederic M. Lord,et al.  On the Statistical Treatment of Football Numbers. , 1953 .

[12]  L. L. Thurstone,et al.  The absolute zero in intelligence measurement. , 1928 .

[13]  Alija Kulenović,et al.  Standards for Educational and Psychological Testing , 1999 .

[14]  G. J. Mellenbergh,et al.  A Unidimensional Latent Trait Model for Continuous Item Responses. , 1994, Multivariate behavioral research.

[15]  J. Michell.  An introduction to the logic of psychological measurement , 1995 .

[16]  D. Laveault.  Modern theories of measurement : problems and issues , 1994 .

[17]  Gerhard H. Fischer,et al.  Derivations of the Rasch Model , 1995 .

[18]  James T. Townsend,et al.  Measurement Scales and Statistics: The Misconception Misconceived , 1984 .

[19]  L. Cronbach,et al.  Construct validity in psychological tests. , 1955, Psychological bulletin.