Methodological considerations for longitudinal investigations of young drivers

IntroductionMotor vehicle crashes (MVCs) are the leading cause of mortality among teenagers. Teen driving research has a longstanding history; however, much of this work is cross-sectional. The Eunice Kennedy Shriver National Institute for Child Health and Human Development funded a study, REACT (Roadway Experiences and Attentional Change in Teens) which combined factorial and longitudinal designs to investigate the independent and joint effects of age and driving experience on driving attention over time among young drivers.MethodLongitudinal methods offer important contributions to teen driving research by enabling characterization of driving trajectories. This paper describes methodological considerations for longitudinal studies of teen drivers. Such considerations are organized into overarching themes, including population, recruitment, enrollment, and retention, throughout this paper. These considerations were compiled as a combination of our own experiences in REACT and previous literature. We elaborate on these considerations below to illustrate the value of each consideration.ResultsIssues encountered are discussed and strategies for dealing with various issues are described. Transportation barriers, scheduling difficulties, and skipped study milestones were among the most frequent challenges; we outline these and other issues encountered in REACT and corresponding considerations for such issues in Table 2. Sharing these experiences should aid future longitudinal investigations of young drivers, which are critically needed to reduce teen MVCs.ConclusionsStudies similar to REACT are considerable undertakings due to the comprehensive nature of longitudinal design. Such investigations must maintain a delicate balance between appropriate amounts of rigor and flexibility in the development of thoroughly defined research questions and theoretically driven frameworks. Key considerations that have contributed to the success of REACT are outlined, challenges encountered throughout data collection are documented, and recommendations based on choices made and lessons learned to inform future longitudinal investigations on young drivers are provided.     

Methodological and computational considerations for multiple correlation analysis

The squared multiple correlation coefficient has been widely employed to assess the goodness-of-fit of linear regression models in many applications. Although there are numerous published sources that present inferential issues and computing algorithms for multinormal correlation models, the statistical procedure for testing substantive significance by specifying the nonzero-effect null hypothesis has received little attention. This article emphasizes the importance of determining whether the squared multiple correlation coefficient is small or large in comparison with some prescribed standard and develops corresponding Excel worksheets that facilitate the implementation of various aspects of the suggested significance tests. In view of the extensive accessibility of Microsoft Excel software and the ultimate convenience of general-purpose statistical packages, the associated computer routines for interval estimation, power calculation, a nd samplesize determination are alsoprovided for completeness. The statistical methods and available programs of multiple correlation analysis described in this article purport to enhance pedagogical presentation in academic curricula and practical application in psychological research.     

Methodological considerations in experiments on imagery acuity

We examine the possible reasons why the results of our recent study on imagery acuity differed from those of an attempted replication by Intons-Peterson and White. Comparison of the two studies suggests that the differences in results are likely to be due to differences in procedures for giving imagery instructions and measuring the fields of resolution, and not to the presence or absence of experimenter bias. Accordingly, we discuss the importance of using skilled and practiced experimenters when conducting imagery acuity experiments. In addition, we address issues raised by Banks concerning the identification of particular levels of functional equivalence in imagery and perception.     

Gender differences in the perception of sexuality: Methodological considerations

The present study of gender differences in the perception of sexuality was designed to systematically vary verbal and nonverbal videotaped cues of a conversation between a male-female dyad. Comparisons were made between 78 males and 99 females who were primarily Caucasian and enrolled in general psychology courses. Participants were able to either see and hear, to only see, or to only hear the same interaction. In the see and hear condition, there were no gender differences in the perception of sexuality; in the see only condition, females rated the actress lower in sexuality; and in the hear only condition, males rated the actress higher in sexuality. Results indicate that methodological differences may account for contradictory findings in prior studies.     

Methodological considerations in the study of delay discounting in intertemporal choice: A comparison of tasks and modes

An experimental comparison of two commonly used delay-discounting procedures (binary choice and fill in the blank) and modes of administration (paper and pencil and computer based) was conducted. Statistically significant main effects were found for task type—steeper discounting was observed in the binary-choice task— but not for mode of administration. As simple evidence of validity, hyperbolic curves consistently provided a better fit to the data than did exponential curves for both tasks. Further, magnitude effects were also observed across conditions. Correlational results varied largely as a function of the discounting index (either k or area under the curve) under consideration. Across the two tasks, discounting indices showed modest levels of reliability [r(AUC)=.33; r(k)=.75]. The findings pointed to refinements for both the methodology and criteria that are used to study delay discounting and raised questions about the commonly assumed relationship between discounting and the construct of impulsivity.     

Methodological considerations in the evaluation of differential components of supplementary education programs

Details procedures to be followed in analyzing multiple program options and time allocation for significant effects. A multiple-option supplementary education program was evaluated by the application of multiple regression analysis as a general data analytic system. One analysis reports the relative merits of supplementary education components when more than one type of program was operated by the same school system and when the criteria for evaluation were end-of-year achievement tests. A second evaluation demonstrates that an analysis of program input variables such as aide time allocation did produce significant improvement in achievement when an analysis of the differential effect of the input variables was considered. An incidental outcome of this study was that significant improvement in reading and mathematics achievement for children in supplementary education programs was more likely to occur with second- and third-grade pupils than with thise at later grade levels.     

Methodological considerations in the evaluation of the convergence of psychiatric diagnoses and parent-informant checklists

Psychiatric diagnoses and objective parent checklists are alternative ways to describe child adjustment problems. There has recently been interest in evaluating the degree of agreement or convergence between these sources of information. This paper addresses three issues neglected by researchers in this area. The appropriateness of the use of indices of sensitivity and specificity to describe the correspondence of diagnoses and checklist scores is questioned. Implications of failure to consider the reliability of diagnoses in interpreting diagnosis-checklist agreement are discussed. Also, possible parameters of diagnosis-checklist agreement that should be identified by researchers are reviewed. Suggestions for improving research in this area are offered.     

Methodological considerations in performing semantic- and translation-priming experiments across languages

Research in the field of bilingualism has had as its principal aim to describe the structure and function of memory for bilingual speakers. A primary technique that has been used to examine bilingual memory is an examination of cross-language word priming (semantic and translation), using the lexical decision and pronunciation tasks. Although studies have, on occasion, revealed greater degrees of word priming from a dominant to a subordinate language, in comparison with the reverse, a careful review of the methodology that has been used reveals a number of issues that render conclusions such as this quite problematic. Parameters of concern include language proficiency, cognate status, masking, control conditions, word frequency and length, stimulus onset asynchrony, relatedness proportion, and nonword ratio. These factors are discussed, as well as recommendations for conducting future empirical research in this area of investigation.     

Escape behavior in neonatal rats: Methodological and psychometric considerations

To determine factors conducive to shock-escape behavior, and which of several measures reflects a learning capability, 5- and 9-day-old rats were given 25 shock-escape training trials in a straight alley in which the grids that comprised the floor ran either vertically or horizontally. Performance was evaluated in terms of speed and competing response measures. Vertically arranged grids were found to facilitate performance in terms of an increased tendency to move in a forward direction. An intrasession decrease in competing responses proved to be the most reliable indicator of learning.     

Vibrotactile signal detection

The theory of signal detectability was applied to vibrotactile sensitivity in two experiments. The first experiment showed The psychometric function to be satisfactorily linear when a sensitivity index of the d family was plotted against the signal intensity expressed in decibels. The second experiment yielded receiver-operating-characteristic (ROC) curves of a familiar form for the yes-no and rating response methods. Reasonably consistent estimates of sensitivity were obtained in the second experiment from the yes-no. rating, and forced-choice methods. The sensitivity indices examined were d’ and d_e’, based on Gaussian density functions; A, based on Rayleigh density functions; and the distribution-free indices, P(A) and F(C). For each type of index a tendency was observed for the forced-choice value to be lower than the yes-no and rating values.