Pilot studies are often recommended by scholars and consultants to address a variety of issues, including preliminary scale or instrument development. Specific concerns such as item difficulty, item discrimination, internal consistency, response rates, and parameter estimation in general are all relevant. Unfortunately, there is little discussion…

This paper includes a nontechnical description of methods for calculating effect sizes in intellectual and developmental disability studies. Different hypothetical studies are used to illustrate how null hypothesis significance testing (NHST) and effect size findings can result in quite different outcomes and therefore conflicting results. Whereas…

One of the main objectives in meta-analysis is to estimate the overall effect size by calculating a confidence interval (CI). The usual procedure consists of assuming a standard normal distribution and a sampling variance defined as the inverse of the sum of the estimated weights of the effect sizes. But this procedure does not take into account…

The study examined adult-child interactions during conversation with respect to the effects of adult paralinguistic speech variations on the speech production of four four-year-old children. Analysis indicated that each child's response time latency (RTL) was significantly longer when the experimenter's RTL was longer. (Author/DB)

The study examined whether stutterers (27 children and 19 adults) subvocalize more slowly than nonstutterers and need more time for overt fluent speech production. Results indicated that a strictly motoric explanation of stuttering is inadequate as stutterers and nonstutterers differ in temporal parameters not only during speech execution, but…

Pressure variations applied by newborns and by infants 1 to 4 months old to rubber nipples were recorded in three different procedures under no-fluid conditions. In the first study, infants were presented for 90 seconds with novel nipples varying in shape and in shape plus material. Results suggested that a developmental trend existed for an…