Neuropsychological changes in children with cancer: The treatment of missing data in longitudinal studies

Researchers conducting longitudinal studies with children or adults are inevitably confronted with problems of attrition and missing data. Missing data in longitudinal studies is frequently handled by excluding from analyses those cases for whom data are incomplete. This approach to missing data is not optimal. On the one hand, if data are missing at random, then dropping incomplete cases ignores information collected on those cases that could be used to improve estimates of population parameters (e.g., means, variances, covariances, and growth rates) and improve the power of significance tests of statistical hypotheses. On the other hand, if data are not missing at random, then dropping incomplete cases leads to biased parameter estimates and hypothesis tests that may be internally and externally invalid. This study uses three years of follow-up data from a longitudinal investigation of neuropsychological outcomes of cancer in children to demonstrate the problems presented by missing data in repeated measures designs and some solutions. In evaluating potential biasing effects of attrition, the study extends previous research on neuropsychological outcomes in pediatric cancer by inclusion of patients whose disease had relapsed, and by comparison of surviving and nonsurviving patients. Although the data presented have specific relevance to the study of neuropsychological outcome in pediatric cancer, the problems of missing data and the solutions presented are relevant to a wide variety of diseases and conditions of interest to researchers in child and adult neuropsychology.     

A METHODOLOGICAL APPROACH TO JOB CLASSIFICATION FOR PERFORMANCE APPRAISAL PURPOSES

This paper illustrates a methodological approach to classifying jobs for the purpose of developing performance evaluation instruments. The approach was to administer a worker-oriented job inventory to 2,023 incumbents across several jobs and several levels of responsibility (rank) in the U. S. Coast Guard. The data from the job inventory were then analyzed using Tucker's Three-Mode Factor Analysis. Output from the three-mode factor analysis was used to identify combinations of jobs and ranks for which separate appraisal instruments could be developed. In addition, output from the three-mode factor analysis was used to suggest the content of the various appraisal instruments. Advantages, applications, and limitations of this approach are discussed.     

On the precision of a euclidean structure

This paper is concerned with the development of a measure of the precision of a multidimensional euclidean structure. The measure is a precision index for each point in the structure, assuming that all the other points are precisely located. The measure is defined and two numerical methods are presented for its calculation. A small Monte Carlo study of the measure's behavior is performed and findings discussed.The authors are indebted to Bert F. Green, Jr., Ronald Helms, Andrea Sedlak, and three anonymous reviewers for their valuable comments on earlier drafts of this paper.     

RIGHTS AND RESPONSIBILITIES ON THE HOME PLANET

Abstract. Earth is the home planet, right for life. But rights, a notable political category, is, unfortunately, a biologically awkward word. Humans, nonetheless, have rights to a natural environment with integrity. Humans have responsibilities to respect values in fauna and flora. Appropriate survival units include species populations and ecosystems. Increasingly the ultimate survival unit isglobal; and humans have a responsibility to the planet Earth. Human political systems are not well suited to protect life atglobal ranges. National boundaries ignore important ecologicalprocesses; national policies do not favor an equitable distribution of sustainable resources. But there are signs of hope.     

Authorial intentions and metaphor comprehension

Three experiments investigated the role of authorial intentions in metaphor comprehension. In these studies, subjects read metaphoric (e.g., A family album is like a museum), literal (e.g., An art gallery is like a museum), and anomalous (e.g., A tortoise shell is like an art gallery) comparisons and rated their degreeof meaningfulness (Experiment 1), made speeded decisions as to whether each phrase was meaningful or not (Experiment 2), or wrote out interpretations of each comparison statement (Experiment 3). The subjects were tolt that the comparisons were written either by famous 20th century poets or by a computer program that randomly generated the statements from a list of words. Our general hypothesis was that knowing that intentional agents (the poets) authored the different comparisons should facilitate subjects' comprehension of the metaphors. Experiment 1 showed that subjects rated both metaphoric and literal comparisons as being more meaningful in the poet condition than when these statements were supposedly written by computer. Experiment 2 demonstrated that subjects were faster in making their meaningfulness judgments for metaphors in the poet condition than in the computer context, but that subjects were also slower in rejecting anomalous comparisons when these were supposedly written by the poets. Experiment 3 indicated that subjects produced more meanings or interpretations for comparisons presumably written by poets than by computer. These results highlight the improtance of implied, authorial intentions in understanding metaphorical statements. We discuss the implications of this work for psycholinguistic theories of figurative language comprehension, as well as for theories of literary interpretation.     

Judgment processes in motivation: Anchoring and adjustment effects on judgment and behavior

The behavioral correlates of human judgment have received little attention from judgment and decision making researchers. One behavioral domain that provides for the study of judgment-behavior relations is task motivation (i.e., the allocation of time and effort to a task). Judgments of contingent relations are primary components of several theories of motivation, including expectancy theories and the theory of behavior in organizations proposed by Naylor, Pritchard, and Ilgen (1980). The characteristics of heuristic judgment processes are hypothesized to affect contingency judgments and thus behavioral allocations of time and effort. This paper examines the effects of the anchoring and adjustment heuristic upon (a) judgments of future effort and performance and (b) upon actual allocations of time and effort using several types of anchoring information. Results indicate that both irrelevant and relevant information have strong anchoring effects on effort and performance judgments, but do not have concomitant effects on behavior. Implications for the role of judgment in motivation and for the link between judgment and behavior are discussed.