Harold D. Delaney

Designing Experiments and Analyzing Data

Whereas there are many experimental design books available, the overall approach, content, and presentation of statistical experimental design in this text are in many ways more complete and broader based than the typical example. Of particular interest is the approach in the first two chapters dealing with statistics in the philosophical, experimental, and scientific sense rather than the strictly mathematical approach so often implied by other authors. The chapter on the Fisher tradition was especially refreshing and certainly interesting in the context of scientific experimentation. The authors have attempted to create a text on experimental design that can be used either as a textbook or as a reference book. It would be difficult to do justice to the content in a typical 18-week course on experimental design. Therefore, I would be more inclined to use the book for a reference and, possibly selected portions, for an introduction to graduate students embarking on their own research study. It will be noticed that the form of the presentation is different from the more computationally oriented texts. The authors have employed a modelcomparison approach that opens up the opportunity to introduce various research models as extenuations or adaptations of simpler models. The method is unique to most texts on research design, and the information presented is more conceptual than computational. The authors rightly assume that the mathematics will be performed by the computer and that the researcher needs to be familiar with the concept of the design rather than the computational techniques. The heart of the presentation comes in chapters 3 and 4. The underlying statistical formulas are introduced in these beginning chapters of Part II. These formulas are used as a basis for all successive chapters. In fact, one would not be required to use the book sequentially even in a classroom environment. But it would be necessary to have the information presented in chapters 3 and 4 well in mind before departing from the sequence outlined. This points to the usefulness of the book as a reference text in that most researchers can turn to any chapter if they have sufficient background or they can read chapters 3 and 4 and then move to specific research models of their choice.

The Mnemonic Keyword Method

The keyword method is a two-stage procedure for remembering materials that have an associative component. In the case of foreign vocabulary learning, for example, the learner first must acquire a stable association between the unfamiliar foreign word and a familiar English word that sounds like a salient part of the foreign word. The acoustically similar English word is the keyword. The learner then encodes a meaningful interaction between the keyword and the foreign word’s definition. The method has been investigated most extensively with respect to recall of definitions from vocabulary words. However, other aspects of vocabulary learning also are considered, as are potential classroom applications of the keyword method based on a variety of curricular content. Future research directions are emphasized throughout the discussion.

Motor deficits after left or right hemisphere damage due to stroke or tumor

Abstract The motor performance of 29 tumor and 43 stroke patients with unilateral left or right hemisphere damage and 40 non-brain-damaged control subjects was compared on six motor tasks. Grip strength, finger tapping, static and vertical groove steadiness, maze coordination and grooved pegboard tasks were administered. All brain-damaged groups performed more poorly than the control group on the hand contralateral to the lesion on all tasks and on the hand ipsilateral to the lesion on the tasks which required greater sensory-motor interaction (static and vertical groove steadiness, maze coordination and grooved pegboard). This pattern of results was the same for the patients with left or right hemisphere damage and was best explained by the hypothesis that the tasks which require greater sensory-motor interaction require more neural control and are more likely to be disrupted after brain damage, regardless of lateralization.

On Using Analysis Of Covariance In Repeated Measures Designs.

The use of analysis of covariance in conjunction with the multivariate approach to analyzing repeated measures designs is considered for designs involving between- and within-subject factors, one dependent variable, and one observation per subject on the covariate. Considerations fundamental to a knowledgeable application of ANCOVA in this situation are detailed including issues related to (1) the validity of the test of the main effect of the within-subject factor, (2) the desirability of an interaction between the within-subject factor and the premeasure score, and (3) the reliability of change scores. Tables providing upper bounds on the correlations of the covariate with change scores are provided. Numerical examples illustrating various analyses of repeated measures designs are also presented.

The Kruskal-Wallis Test and Stochastic Homogeneity

For the comparison of more than two independent samples the Kruskal-Wallis H test is a preferred procedure in many situations. However, the exact null and alternative hypotheses, as well as the assumptions of this test, do not seem to be very clear among behavioral scientists. This article attempts to bring some order to the inconsistent, sometimes controversial treatments of the Kruskal-Wallis test. First we clarify that the H test cannot detect with consistently increasing power any alternative hypothesis other than exceptions to stochastic homogeneity. It is then shown by a mathematical derivation that stochastic homogeneity is equivalent to the equality of the expected values of the rank sample means. This finding implies that the null hypothesis of stochastic homogeneity can be tested by an ANOVA performed on the rank transforms, which is essentially equivalent to doing a Kruskal-Wallis H test. If the variance homogeneity condition does not hold then it is suggested that robust ANOVA alternatives performed on ranks be used for testing stochastic homogeneity. Generalizations are also made with respect to Friedman’s G test.

Attachment to God and Implicit Spirituality: Clarifying Correspondence and Compensation Models

This article empirically investigates two alternative, competing hypotheses regarding human attachment patterns and attachment patterns with respect to peoples spiritual experiences of relationship with God. The correspondence model posits that attachment patterns with humans correspond to, or are reflected in attachment patterns in individuals’ experiences of God. The compensation model, in contrast proposes that attachment patterns with humans do not correspond to God attachment patterns presumably because God functions as a substitute attachment figure for those with insecure human attachments. Overall, the evidence has been somewhat mixed, with some findings supporting correspondence and some supporting compensation. It is argued here that this is due to limitations of the conceptual models, more specifically, lack of clarity regarding the compensation model, and the limited way in which spirituality and religiousness has been conceptualized and measured. We propose a conceptual distinction between implicit spiritual functioning and explicit spiritual functioning, which reflect two separate ways of knowing and processing emotional information: explicit knowledge and implicit relational knowledge (Stern et al., 1998). Based on this distinction, we propose a conceptual model arguing that correspondence operates at implicit levels of spiritual experience, and that human attachment patterns are not associated with explicit spiritual functioning. Results overall provided strong support for this model.

Community Reinforcement Approach in the Treatment of Opiate Addicts

The authors studied the efficacy of the community reinforcement approach (CRA) as compared to standard counseling in opiate-dependent patients on methadone maintenance. One hundred eighty subjects were randomized to three treatment conditions: standard, CRA, and CRA with relapse prevention (CRA/RP). Of these, 151 subjects were followed up 6 months after intake. Since few of the RP sessions had been concluded at the 6-month follow-up, the two CRA groups were combined for analyses. Weekly urinalysis drug screens and Addiction Severity Index (ASI) scores at intake and 6 months were compared. The combined CRA groups did significantly better than the standard group in the following areas: consecutive opiate-negative urinalysis (3 weeks), and the 6-month ASI drug composite score. These results support the benefit of adding CRA strategies to the treatment of patients who are opiate dependent and on methadone maintenance. Because of insufficient treatment exposure to RP at the 6-month follow-up, the additive effect of RP could not be adequately evaluated; further follow-up will be required.

Dichotomization, Partial Correlation, and Conditional Independence.

It was recently demonstrated that performing median splits on both of two predictor variables could sometimes result in spurious statistical significance instead of lower power. Not only is the conventional wisdom that dichotomization always lowers power incorrect, but the current article further demonstrates that inflation of apparent effects can also occur in certain cases where only one of two predictor variables is dichotomized. In addition, we show that previously published formulas claiming that correlations are necessarily reduced by bivariate dichotomization are incorrect. While the magnitude of the difference between the correct and incorrect formulas is not great for small or moderate correlations, it is important to correct the misunderstanding of partial correlations that led to the error in the previous derivations. This is done by considering the relationship between partial correlation and conditional independence in the context of dichotomized predictor variables.

The college drinker's check-up: Outcomes of two randomized clinical trials of a computer-delivered intervention

The objective of the study was to evaluate the effectiveness of a computer-delivered intervention (CDI) to reduce heavy drinking and alcohol-related problems in college students in two randomized clinical trials. In Experiment 1, we randomized 144 students to either the CDI or an assessment-only control group with follow-ups at 1 and 12 months. In Experiment 2, we randomized 82 students to either the CDI or a delayed-assessment control group with follow-up at 1 month. In Experiment 1, participants in both groups significantly reduced their drinking at both follow-ups. Compared to the control group, the CDI group reduced their drinking significantly more at 1 and 12 months on three drinking measures at α < .05. Using a more conservative, Bonferroni-adjusted criterion yielded one significant difference in a measure of heavier drinking at the 1 month follow-up. The mean between-groups effect sizes were d = .34 and .36 at 1 and 12 months, respectively. Experiment 2. Compared to the delayed assessment control group, the CDI group significantly reduced (by the Bonferroni-adjusted criterion) their drinking on all consumption measures. These results support the effectiveness of the CDI with heavy drinking college students when used in a clinical setting. In addition, the significant reductions in typical drinking in the control group in Experiment 1 and not in Experiment 2 combined with comparable baseline characteristics suggests that the control group in Experiment 1 demonstrated assessment reactivity.

Videotaped Training in Alcohol Counseling for Obstetric Care Practitioners: A Randomized Controlled Trial

OBJECTIVE To determine the feasibility of videotaped training for obstetric care practitioners in motivational interviewing skills that could be used in brief patient consultations on problem drinking. METHODS Thirty health care practitioners participated in a clinical trial using a 20-minute videotape to instruct them in motivational interviewing. Participants engaged in a pretest roleplay with an actress playing a drinking pregnant woman. Those randomly assigned to the experimental condition watched the motivational interviewing videotape. Control condition participants watched a 20-minute docudrama of a pregnant problem drinker. Both groups then engaged in a post-test roleplay similar to the pretest. Behavioral ratings of the roleplays and participant evaluations of the motivational interviewing video constituted the outcome measures. RESULTS Participant evaluations indicated that the training video was clear in explaining and demonstrating the principles and skills of motivational interviewing. Change in behavioral ratings from pretest to post-test showed significant differences in motivational interviewing skills between the experimental and control groups. Obstetric care practitioners who viewed the training video were rated as showing greater empathy, minimizing patient defensiveness, and supporting womens beliefs in their ability to change. CONCLUSION Obstetric care practitioners can improve their alcohol intervention skills through the use of a 20-minute videotaped instruction in motivational interviewing. Clinicians who improve their skills in motivational interviewing can intervene more effectively with their drinking pregnant patients. Using motivational interviewing with this population holds promise for helping prevent alcohol-related health problems.