A proposed solution for the age x cohort x period issue in lifespan research uses all data, even with missing cells; can be used for repeated measures designs or designs in which new subjects are measured at each period; and allows assessment of each main effect and two-way interaction. (SLD)

Examines the problem of aging of books in university libraries and presents a mathematical model of the aging process. Indexes for the aging time limit, over-age book rate, and aging rate are suggested; use of the mean unit price is considered; and countermeasures for control of the aging process are proposed. (four references) (MES)

Effects of the following methods for linking metrics on detection of differential item functioning (DIF) were compared: (1) test characteristic curve method (TCC); (2) weighted mean and sigma method; and (3) minimum chi-square method. With large samples, results were essentially the same. With small samples, TCC was most accurate. (SLD)

A method is proposed for sequential evaluation of reliability of psychometric instruments. Sample size is unfixed; a test statistic is computed after each person is sampled and a decision is made in each stage of the sampling process. Results from a series of Monte-Carlo experiments establish the method's efficiency. (SLD)

Two methods of computing test equating coefficients under item response theory by the following authors are compared: (1) B. H. Loyd and H. D. Hoover (1980); and (2) M. L. Stocking and F. M. Lord (1983). Conditions under which the method of Stocking and Lord is preferable are described. (SLD)

A model integrating latent trait and latent class theories in characterizing individual performance on the basis of qualitative understanding is presented. This HYBRID model is illustrated through experiments with 119 Air Force technicians taking a paper-and-pencil test and 136 Air Force technicians taking a computerized test. (SLD)

Surveys in which one can observe--after sample selection--that each sample member belongs to one or more aggregations are considered. A formula for the probability that a given aggregation contains at least one sample member is applied to eighth grade data from the National Educational Longitudinal Study of 1988 (NELS:88). (TJH)

Applies chaos theory to complex social organization, beginning with a mathematical definition of chaos. Shows how a nonlinear equation might be used to describe organization. The conclusion section identifies three approaches to analyzing chaos in social organization: metaphorical analysis, mathematical modeling, and data collection. (36…

Estimating item parameters from a two-parameter normal ogive model is considered using Gibbs sampling to simulate draws from the joint posterior distribution of ability and item parameters. The method gives marginal posterior density estimates for any parameter of interest, as illustrated using data from a 33-item mathematics placement…

Methodology is suggested for several statistical procedures to detect polytomously scored items that function differently for two subgroups of examinees. The 3 methods are alternative ways of combining the data from 2 x "k" tables. Simulation results demonstrate the superiority of two of the methods, designated HW1 and HW3. (SLD)

An implementation of the Gauss-Newton algorithm for the analysis of covariance structure that is specifically adapted for high-level computer languages is reviewed. This simple method for estimating structural equation models is useful for a variety of standard models, as is illustrated. (SLD)

A strategy is described for dealing with measurement situations in which certain categories of responses are null, that is, persons do not respond in certain categories to certain items. The method is described for the partial credit model while maintaining the integrity of the original response framework. (SLD)

Techniques for adjusting census figures are discussed, with a focus on sampling error, uncertainty of estimates resulting from the luck of sample choice. Computer simulations illustrate the ways in which the smoothing algorithm may make adjustments less, rather than more, accurate. (SLD)

To assess cross-observer agreement on personality profiles, an Index of Profile Agreement and an associated coefficient are proposed that take into account both the difference between the ratings and the extremes of their mean. Data from the Revised NEO Personality Inventory for 250 peer ratings/self-reports and 68 spouse ratings/self-reports…

A two-stage process that considers the multidimensionality of tests under the framework of unidimensional item response theory is described and evaluated. Findings from a simulation indicate that gains in estimation robustness and score interpretation are possible with almost no sacrifice of goodness of fit when using this two-stage approach. (SLD)