Reliability and validity of self-report data provided by 178 mentally ill homeless persons were generally favorable. Self-reports of service use also generally agreed with treatment staff estimates, providing further validity evidence. Researchers and administrators can be relatively confident in using such data. (SLD)

A Monte Carlo simulation explored how to optimize power in the extreme groups strategy when sampling from nonnormal distributions. Results show that the optimum percent for the extreme group selection was approximately the same for all population shapes, except the extremely platykurtic (uniform) distribution. (SLD)

Four things are recommended to minimize the influence or importance of statistical significance testing. Researchers must not neglect to add "statistical" to significant and could interpret results before giving p-values. Effect sizes should be reported with measures of sampling error, and replication can be built into the design. (SLD)

The delta method was used to derive standard errors (SES) of the Levine observed score and Levine true score linear test equating methods using data from two test forms. SES derived without the normality assumption and bootstrap SES were very close. The situation with skewed score distributions is also discussed. (SLD)

Use of linear combinations of Fisher's "z" transformations as a combined test for the common correlation parameter based on "k" independent sample correlations has been previously studied. This article considers additional "z" additive properties and methods of combining independent studies when planning the number of…

A distribution theory is derived for a G. V. Glass-type (1976) estimator of effect size from studies involving paired comparisons. The possibility of combining effect sizes from studies involving a mixture of related and unrelated samples is also explored. Resulting estimates are illustrated using data from previous psychiatric research. (SLD)

Describes methods to increase the participation of Hispanic residents in community-needs-assessment activities based on experiences in Tampa (Florida). Includes suggestions for defining the population, estimating population size, selecting the sample, translating instruments, and administering the survey. (SLD)

This article first reviews the research establishing the need to sample text-level discourse in assessment of language abilities and identifies issues for clinicians constructing their own language sampling protocols. It then describes two protocols for use in school- and clinic-based settings, with examples of how these protocols have been…

Introduces some of the considerations behind the teaching of research methodology at the Royal School of Library and Information Science (Denmark) at the masters level. Discusses information retrieval experiments; sampling problems; the concept of a model; and statistical analysis and its role in information retrieval experiments. (Contains 25…

Makes the case that science is best served when researchers focus on the size of effects and their practical significance. Advocates the use of confidence intervals for deciding whether chance or sampling variability is an unlikely explanation for an observed effect. Calls for more emphasis on effect sizes in the next edition of the American…

Studied the sampling variability of estimated variance components using data collected over several years for a listening and writing performance assessment and evaluated the stability of estimated measurement precision. Results indicate that the estimated variance components varied from one year to another and suggest that the measurement…

Describes a hands-on demonstration of the concept of the sampling distribution of the mean using M&M's candy. Compares the effectiveness of the candy demonstration with that of a comparable demonstration using a textbook example. Reports that students exposed to the candy example performed better on a subsequent examination. (DSK)

Explores the uncertainty inherent in measurement, sampling, repeatability, and prediction. Emphasizes the inextricable connection of mathematics and science. (SAH)

Provides details on the instrument development, sample design, data collection, and data analysis procedures for the 1998 National Assessment of Educational Progress (NAEP) national and state assessments. Includes information necessary to show adherence to testing standards of professional organizations. (SLD)

Examines assumptions underlying the employment of group means in communication research. Suggests a sample mean cannot be assumed to be a "good" statistic when the response vector represents different individuals' outcomes versus different outcomes of an individual. Notes implications for communication research. (SR)