The sensitivity of marginal maximum likelihood estimation of item and ability (theta) parameters was examined when prior ability distributions were not matched to underlying ability distributions. Thirty sets of 45-item test data were generated. Conditions affecting the accuracy of estimation are discussed. (SLD)

Inference is considered for the marginal distribution of "X" when ("X", "Y") has a truncated bivariate normal distribution. The "Y" variable is truncated, but only the "X" values are observed. A sample of 87 Otis test scores is shown to be well described by this model. (SLD)

The National Survey of Student Engagement (NSSE) provides participating schools an Institutional Report that includes (among many documents) mean comparisons, frequency distributions, and student respondent data as part of its standard reporting package. Sifting through all this data can leave even experienced researchers wondering where to start…

Given the fragmented structure of child-care assistance in the United States, it has been difficult to obtain accurate estimates of which families are assisted, through which mechanisms, and at what level. Making use of survey data from New York City, we analyze the distribution of several forms of public child-care assistance. Results suggest…

Comparing variability of test scores across alternate forms, test conditions, or subpopulations is a fundamental problem in psychometrics. A confidence interval for a ratio of standard deviations is proposed that performs as well as the classic method with normal distributions and performs dramatically better with nonnormal distributions. A simple…

The notion of optimality is often invoked informally in the literature on metacognitive control. We provide a precise formulation of the optimization problem and show that optimal time allocation strategies depend critically on certain characteristics of the learning environment, such as the extent of time pressure, and the nature of the uptake…

This research examines the effect of increased testing time by comparing the four performance indices of randomly equivalent examinee subpopulations on sections of similar content and difficulty administered at different times on three SAT administrations. A variety of analyses were used in this study and found no evidence that the current SAT…

While most existing online learning environments cater for needs identified during the 1990s, a new generation of digital students has emerged in the developed world. Digital students are young adults who have grown up with digital technologies integrated as an everyday feature of their lives. Digital students use technology differently, fluidly…

M. J. Kolen, B. A. Hanson, and R. L. Brennan (1992) presented a procedure for assessing the conditional standard error of measurement (CSEM) of scale scores using a strong true-score model. They also investigated the ways of using nonlinear transformation from number-correct raw score to scale score to equalize the conditional standard error along…

A study examined whether, holding work experience and sex constant, exposure to vocational education during secondary school was related to incidence of nonfatal work-related injuries. Data were from the 1987 and 1988 annual National Longitudinal Surveys of Labor Market Experience interviews of young adults who were between 14 and 21 years old on…

Many testing programs include a section of optional questions in addition to mandatory parts of a test. These optional parts of a test are not often truly parallel to one another, and groups of examinees selecting each optional test section are not equivalent to one another. This paper provides a general method based on missing-data methods for…

In educational research, nonessential factors are commonly ignored and when accounted for, they are often treated statistically as fixed effects. Yet many researchers in these situations generalize their findings beyond the specific levels selected; however, the analyses may require treating the factor as a random effect. Such inappropriate…

By employing a concomitant variable, researchers can reduce the error, increase the precision, and maximize the power of an experimental design. Blocking and analysis of covariance (ANCOVA) are most often used to harness the power of a concomitant variable. Whether to block or covary and how many blocks to be used if a block design is chosen…

The purpose of this investigation was to examine historical changes in aptitude scores. Recent literature suggesting a decline in the quality of the U.S. workforce is reviewed, and an expectation that score distributions on aptitude tests have shifted in a negative direction is presented. Archival analyses of normative data for the Short…

The purpose of this study was to develop a single procedure for comparing population variances which could be used for distribution forms. Bootstrap methodology was used to estimate the variability of the sample variance statistic when the population distribution was normal, platykurtic and leptokurtic. The data for the study were generated and…