A split-sample replication stopping rule for hierarchical cluster analysis is compared with the internal criterion previously found superior by Milligan and Cooper (1985) in their comparison of 30 different procedures. Situations under which the methods are equivalent or not equally useful are discussed. (SLD)

Explains how the Gibbs sampler can be applied to obtain a sample from the posterior distribution over the parameters of a structural equation model. Presents statistics to use to summarize marginal posterior densities and model checks using posterior predictive p-values. (SLD)

Investigated the item-parameter recovery characteristics of a Gibbs sampling method (J. Albert, 1992) for item-response theory item-parameter estimation and compared them to those from the BILOG computer program. Item-parameter recoveries were similar for both approaches for larger data sets, but overall, BILOG performance was superior. (SLD)

Continues a series on topics in research methodology, statistics, and data analysis techniques for the library and information sciences. Focuses on the basics of sampling for surveys or experimental work, including rationale, terminology, technique, alternative methods, and sample size. (Author/LRW)

The sampling interpretation of confidence intervals and hypothesis tests is discussed in the context of conditional maximum likelihood estimation. Three different interpretations are discussed, and it is shown that confidence intervals constructed from the asymptotic distribution under the third sampling scheme discussed are valid for the first…

Contributes to journalism research by investigating what type and size of probability sample will allow valid inference. Tests the efficiency of probability samples of issues of two monthly consumer magazines over five years, finding a stratified sample more efficient than a simple random sample. (SR)

Discusses sampling bias problems in the use of the greatest lower bound (g.l.b.) to reliability and offers explicit expressions for the second order derivatives. This yields closed form expression for the asymptotic bias of both the g.l.b. and its numerator. Illustrates the approach through a numeric example. (SLD)

Studies concentration aspects of bibliographies, particularly the impact of incompleteness on its concentration values (i.e. its degree of inequality of production of its sources). Models incompleteness by different sampling techniques and discusses implications for the measurement of production inequality in incomplete bibliographies. (Author/LRW)

To determine the extent and nature of alcohol screening and referral services provided by college health centers, the authors conducted a state-stratified, random sampling of 25% of 327 4-year accredited US colleges and universities with health centers. Of the 249 survey respondents, 32% routinely screened students for alcohol use. Urban, public,…

In 1987 the federal government permitted states to raise the speed limit on their rural interstate roads, but not on their urban interstate roads, from 55 mph to 65 mph. Since the states that adopted the higher speed limit must have valued the travel hours they saved more than the fatalities incurred, this institutional change provides an…

The meta-analysis of coefficient alpha across many studies is becoming more common in psychology by a methodology labeled reliability generalization. Existing reliability generalization studies have not used the sampling distribution of coefficient alpha for precision weighting and other common meta-analytic procedures. A framework is provided for…

The authors evaluated 4 sequential sampling models for 2-choice decisions--the Wiener diffusion, Ornstein-Uhlenbeck (OU) diffusion, accumulator, and Poisson counter models--by fitting them to the response time (RT) distributions and accuracy data from 3 experiments. Each of the models was augmented with assumptions of variability across trials in…

To assess the reliability of congeneric tests, specifically designed reliability measures have been proposed. This paper emphasizes that such measures rely on a unidimensionality hypothesis, which can neither be confirmed nor rejected when there are only three test parts, and will invariably be rejected when there are more than three test parts.…

The DA-T Gibbs sampler is proposed by Maris and Maris (2002) as a Bayesian estimation method for a wide variety of "Item Response Theory (IRT) models". The present paper provides an expository account of the DA-T Gibbs sampler for the 2PL model. However, the scope is not limited to the 2PL model. It is demonstrated how the DA-T Gibbs…

This article provides a profile of a range of important variables for assessing diversity among different Latino groups from the National Latino and Asian American Study (NLAAS). The NLAAS is a nationally representative study of the mental health needs and mental health services use of the Latino population of the United States. The NLAAS employs…