Using logistic regression to estimate delay-discounting functions.

The monetary choice questionnaire (MCQ) and similar computer tasks ask preference questions in order to ascertain indifference, the perceived equivalence of immediate versus larger delayed rewards. Indifference data are then fitted with a hyperbolic function, summarizing the decline in perceived value with delay time. We present a fitting method that estimates the hyperbolic parameter k directly from survey responses. Binary preferences are modeled as a function of time (X2) and a transformed reward ratio (X1), yielding logistic regression coefficients beta 2 and beta 1. The hyperbolic parameter emerges as k = beta 2/beta 1, where the logistic predicted p = .5 (the definition of indifference). The MCQ was administered to 1,073 adolescents and was scored using both standard and logistic methods. The means for In(k) were similar (standard, -4.53; logistic, -4.51), and the results were highly correlated (rho = .973). Simulated MCQ data showed that k was unbiased, except where beta 1 > or = -1, indicating a vague survey response. Jackknife standard errors provided excellent coverage.     

The structure of lexical concepts

Jerry Fodor (Concepts: Where cognitive science went wrong. New York: Oxford University Press, 1998) famously argued that lexical concepts are unstructured. After examining the advantages and disadvantages of both the classical approach to concepts and Fodor’s conceptual atomism, I argue that some lexical concepts are, in fact, structured. Roughly stated, I argue that structured lexical concepts bear a necessary biconditional entailment relation to their structural constituents. I develop this account of the structure of lexical concepts within the framework of Pavel Tichy’s (The foundations of Frege’s logic. Berlin, New York: De Gruyter, 1988) theory of constructions. I argue that concepts are constructions which can be combined by way of Tichy’s construction-forming operations of composition and closure and an additional operation, simplification, which I propose in section 6. The last of these construction-forming operations plays a central role in my account of lexical concept structure. Stated generally, structured lexical concepts are a result of simplifying their structural constituents.     

Common language effect size for correlations

The Pearson correlation coefficient can be translated to a common language effect size, which shows the probability of obtaining a certain value on one variable, given the value on the other variable. This common language effect size makes the size of a correlation coefficient understandable to laypeople. Three examples are provided to demonstrate the application of the common language effect size in interpreting Pearson correlation coefficients and multiple correlation coefficients.     

Behavioral and Emotional Rating Scale: Two Studies of Convergent Validity

As the field of mental health services shifts its focus to early intervention, the need to develop valid and reliable measures of young children's behavioral functioning is clear. Traditional assessment instruments have focused on deficits, problems, and pathologies to the exclusion of strengths and competencies. However, assessing child strengths provides parents, direct service providers, and educators with a more holistic view of the child's functioning and an understanding of skills from which individualized treatment and education plans may be written. The Behavioral and Emotional Rating Scale (BERS; Epstein & Sharma, 1998) is a strength-based instrument designed to identify children's behavioral and emotional strengths. The psychometrics of the BERS has been demonstrated through several studies; however, the focus has mainly been on older age students. We sought to assess the convergent validity of the BERS with kindergarten children. The results of these two studies provide further support of the psychometric characteristics of the BERS and indicate its appropriateness with young children.     

Methods to decrease attrition in longitudinal studies with adolescents

A summary of methods to decrease attrition in longitudinal school-based studies conducted with adolescents beginning junior high schools or middle schools is presented. These include collection of contact information about students, additional days to collect data from absentee students, data collection in new high schools once students graduate from junior high schools or middle schools, sending questionnaires by mail, and conducting telephone or home interviews.