A critical review of the assumptions underlying drug testing

Current drug screening programs are based on a set of assumptions: That drug use adversely affects productivity, that available tests are accurate and cost-effective means of detecting and reducing drug use, and that drug testing is legal. When analyzed in the light of available evidence, little support was found for these assumptions. Used properly, drug testing may play a role in the overall management of employee performance; used improperly, it represents a profound threat to individual rights. Recommendations for additional research and for employers planning to use drug screening are offered.     

College-level instruction: derived relations and programmed instruction

Recent research has demonstrated the effectiveness of programmed instruction that integrates derived relations to teach college-level academic material. This method has been demonstrated to be effective and economical in the teaching of complex mathematics and biology concepts. Although this approach may have potential applications with other domains of college learning, more studies are needed to evaluate important technological variables. Studies that employ programmed instruction are discussed in relation to future directions for research.     

Testing the assumptions underlying tetrachoric correlations

A method is proposed for empirically testing the appropriateness of using tetrachoric correlations for a set of dichotomous variables. Trivariate marginal information is used to get a set of one-degree of freedom chi-square tests of the underlying normality. It is argued that such tests should preferrably preceed further modeling of tetrachorics, for example, modeling by factor analysis. The assumptions are tested in some real and simulated data.Presented at the Psychometric Society meeting in Santa Barbara, California, June 25–26, 1984. The research of the first author was supported by Grant No. SES-8312583 from the National Science Foundation.     

Using mediators and moderators to test assumptions underlying culturally sensitive therapies: an exploratory example

Factors hypothesized to impact Asian American responses to counseling were tested as mediators and moderators of perceived counselor credibility and working alliance. Asian and European American college students (N = 182) were assigned randomly to view simulated directive or nondirective therapy approaches. Mediation analyses examined whether ethnic group differences in initial perceptions were accounted for by therapist understandability and previous therapy experiences. Moderation analyses examined whether expectations for directive therapy, ambiguity tolerance, and resistance influenced initial perceptions across directive and nondirective counseling. Asian Americans rated the counseling approaches significantly less favorably than Europeans Americans. A significant mediation effect was found for therapist understandability, whereas a significant moderation effect was found for expectation for directive therapy on initial perceptions of counselor credibility.     

The assumptions underlying the generalized matching law

Allen (1981) derived the power-function generalization of the matching law from a functional equation involving relative response rates on three concurrently available schedules of reinforcement. This paper defines the conditions (relative homogeneity and independence) under which a more general class of behavioral laws reduces to the power law. The proof also removes two deficiencies of Allen's result (discussed by Houston, 1982), which are, first, that his derivation produces a power law without a bias coefficient, and second, that it holds only for experiments with three or more concurrent schedules.     

Effects of imposed postfeedback delays in programmed instruction

Imposed postfeedback delays promote discrimination training; the present experiments determined whether they also improve performance in programmed instruction. In two experiments, college students completed 45 sets of Holland and Skinner's (1961) programmed text on behavior analysis in a computerized format in a three-component multiple schedule. In Experiment 1, the conditions were (a) no delay between questions, (b) a 10-s delay after each question (noncontingent delay), and (c) a 10-s delay after each question answered incorrectly (contingent delay). Noncontingent delay produced better performance than no delay and contingent delay. To determine whether performance increased in the noncontingent delay condition because subjects studied the material during delay periods, Experiment 2 tested three conditions: (a) no delay between questions, (b) a 10-s delay after each question (noncontingent delay), and (c) a 10-s delay after each question with the screen blank during the delay period. Noncontingent delay produced better performance than no delay, but there was no difference in performance between no delay and noncontingent delay with blank screen. Hence, noncontingent delay improved performance because students used delay periods to study. Furthermore, subjects preferred noncontingent delay to the other conditions, and session time increased only slightly.     

Procedures for giving immediate reinforcement in programmed instruction

This paper describes several procedures for using special chemicals or inks to immediately reinforce a response to a multiple-choice stimulus. These procedures are known to be currently available, economically feasible, and administratively practical.     

A test of the dimensionality assumptions of Rotter's Internal-External scale

Summary: Examined two assumptions about the dimensionality of Rotter's I-E scale: First, the bipolarity of the two statements within each item pair; second, the unidimensionality of the overall construct. A revised I-E scale was constructed in which each of the statements from the original I-E scale was presented separately and the 367 subjects could accept or reject them independently. Correlations between statements within item pairs were low anti negative with only seven exceeding a value of -.20. The responses to the statements were factor analyzed resulting in six interpretable factors when rotated. Of the 23 item pairs, there were 11 pairs which loaded on the same factor in opposite directions while the other 12 loaded on different factors or on the same factor but in the same direction. A subsample consisting of 152 subjects also took the original I-E scale. The correlations between factor scores on the 6 factors and the original I-E score varied from .15 to .52. Both assumptions regarding Rotter's I-E scale were found untenable. Instead, it is suggested that the forced choice format be abandoned and the construct be thought of as a second order factor.     

A memory-based model of posttraumatic stress disorder: evaluating basic assumptions underlying the PTSD diagnosis

In the mnemonic model of posttraumatic stress disorder (PTSD), the current memory of a negative event, not the event itself, determines symptoms. The model is an alternative to the current event-based etiology of PTSD represented in the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; American Psychiatric Association, 2000). The model accounts for important and reliable findings that are often inconsistent with the current diagnostic view and that have been neglected by theoretical accounts of the disorder, including the following observations. The diagnosis needs objective information about the trauma and peritraumatic emotions but uses retrospective memory reports that can have substantial biases. Negative events and emotions that do not satisfy the current diagnostic criteria for a trauma can be followed by symptoms that would otherwise qualify for PTSD. Predisposing factors that affect the current memory have large effects on symptoms. The inability-to-recall-an-important-aspect-of-the-trauma symptom does not correlate with other symptoms. Loss or enhancement of the trauma memory affects PTSD symptoms in predictable ways. Special mechanisms that apply only to traumatic memories are not needed, increasing parsimony and the knowledge that can be applied to understanding PTSD.