To date, small sample problems with latent growth models (LGMs) have not received the amount of attention in the literature as related mixed-effect models (MEMs). Although many models can be interchangeably framed as a LGM or a MEM, LGMs uniquely provide criteria to assess global data-model fit. However, previous studies have demonstrated poor…

A jack knife is a pocket knife that is put to many tasks, because it's ready to hand. Often there could be a better tool for the job, such as a screwdriver, a scraper, or a can-opener, but these are not usually pocket items. In statistical terms, the expression implies making do with what's available. Another simile, of an extreme situation, is…

Using a computer-based Monte Carlo approach to generate item responses, the results of this study indicate that, when item discrimination indices are considered, item-examinee sampling procedures having the same number of observations have different standard errors in estimating both test mean and test variance. With certain types of tests, a…

Using "Books for College Libraries" as a standard reference against which to compare the Purdue University Calumet Campus library collection, a quantitative analysis of the library's holdings in various subject areas was done during the 1973-74 academic year. For each of the 65 subject areas selected, randomly chosen entries in…

Discusses the idea that with larger cohorts of the very old, subjects in their 80s and 90s will be increasingly sought as respondents. Points out various steps that need to be taken to assure that this older group will be represented by the ailing as well as the healthy community residents. (Author/EJT)

This is one of a series of eight short monographs intended to aid practicing educators in planning and conducting accountability programs in schools. This booklet discusses how to determine a sampling method that is appropriate to the objectives of a particular research or evaluation effort. Short sections focus in turn on why and when to sample,…

Multiple matrix sampling is a data collection technique that ensures accuracy and efficiency in group performance. It has been widely used in large-scale curriculum evaluation since the 1980s. However, the design does not always fully embrace the dynamics of local evaluation demands. The purpose of this study is to introduce a modified matrix…

Sampling distributions for ten tests for comparing population variances in a two group design were generated for several combinations of equal and unequal sample sizes, population means, and group variances when distributional forms differed. The ten procedures included: (1) O'Brien's (OB); (2) O'Brien's with adjusted degrees of freedom; (3)…

The purpose of this study was to empirically determine the effects of quantified violations of the underlying assumptions of parametric statistical tests commonly used in educational research, namely the correlation coefficient (r) and the t test. The effects of heterogeneity of variance, nonnormality, and nonlinear transformations of scales were…

This paper examines how various equating methods are affected by: (1) sampling error; (2) sample characteristics; and (3) characteristics of anchor test items. It reviews empirical studies that investigated the invariance of equating transformations, and it discusses empirical and simulation studies that focus on how the properties of anchor tests…