Crewmember performance before, during, and after spaceflight

The development of technologies for monitoring the welfare of crewmembers is a critical requirement for extended spaceflight. Behavior analytic methodologies provide a framework for studying the performance of individuals and groups, and brief computerized tests have been used successfully to examine the impairing effects of sleep, drug, and nutrition manipulations on human behavior. The purpose of the present study was to evaluate the feasibility and sensitivity of repeated performance testing during spaceflight. Four National Aeronautics and Space Administration crewmembers were trained to complete computerized questionnaires and performance tasks at repeated regular intervals before and after a 10-day shuttle mission and at times that interfered minimally with other mission activities during spaceflight. Two types of performance, Digit-Symbol Substitution trial completion rates and response times during the most complex Number Recognition trials, were altered slightly during spaceflight. All other dimensions of the performance tasks remained essentially unchanged over the course of the study. Verbal ratings of Fatigue increased slightly during spaceflight and decreased during the postflight test sessions. Arousal ratings increased during spaceflight and decreased postflight. No other consistent changes in rating-scale measures were observed over the course of the study. Crewmembers completed all mission requirements in an efficient manner with no indication of clinically significant behavioral impairment during the 10-day spaceflight. These results support the feasibility and utility of computerized task performances and questionnaire rating scales for repeated measurement of behavior during spaceflight.     

Unwanted memories of assault: what intrusion characteristics are associated with PTSD?

Intrusive memories are common in the immediate aftermath of traumatic events, but neither their presence or frequency are good predictors of the persistence of posttraumatic stress disorder (PTSD). Two studies of assault survivors, a cross-sectional study (N=81) and a 6-month prospective longitudinal study (N=73), explored whether characteristics of the intrusive memories improve the prediction. Intrusion characteristics were assessed with an Intrusion Interview and an Intrusion Provocation Task. The distress caused by the intrusions, their "here and now" quality, and their lack of a context predicted PTSD severity. The presence of intrusive memories only explained 9% of the variance of PTSD severity at 6 months after assault. Among survivors with intrusions, intrusion frequency only explained 8% of the variance of PTSD symptom severity at 6 months. Nowness, distress and lack of context explained an additional 43% of the variance. These intrusion characteristics also predicted PTSD severity at 6 months over and above what could be predicted from PTSD diagnostic status at initial assessment. Further predictors of PTSD severity were rumination about the intrusive memories, and the ease and persistence with which intrusive memories could be triggered by photographs depicting assaults. The results have implications for the early identification of trauma survivors at risk of chronic PTSD.     

The Program Environment Scale: Assessing Client Perceptions of Community-Based Programs for the Severely Mentally Ill

The Program Environment Scale (PES) was developed for use with clients of community-based programs for the severely mentally ill. It is intended to fill the gap in available tools for assessing clients' perceptions of program functioning as it affects their quality of life in a program. Formal pretests were conducted with 121 clients at 12 randomly selected programs near Washington, DC. The final field test used a revised form (29 domains; 129 items) with 221 clients in 22 programs selected randomly throughout the U.S., including Clubhouse, day treatment, psychosocial rehabilitation, and social club programs. Twenty-three subscales met at least five of eight psychometric criteria for internal consistency and discriminant validity. A 24th subscale was retained because of its substantive importance. Successful subscales cover program atmosphere and interactions (program cares about me, energy level, friendliness, openness, staff-client and client-client respect, reasonable rules, availability of positive physical contact, protection from bad touch, staff investment in their jobs, and confidentiality), client empowerment/staff-client equality (program and treatment empowerment, egalitarian space use), and service components (support for paid work, work importance, emergency access, family activities, housing, public benefits, community activities, medications, substance abuse, and continuity). Subscale validity is indicated by associations of specific service offerings with scores on scales measuring client perceptions of those services, and by an ability to differentiate among program models (i.e., Clubhouses, day treatment programs, and psychosocial rehabilitation programs look different from each other). Subscale scores were not influenced by client characteristics (gender, race, age, diagnosis, number of hospitalizations, length of time in program). The final scale has 97 items and takes about 25 minutes to complete. The PES succeeds in measuring different aspects of programs as clients perceive them. In the programs we visited, directors felt the PES covers the important things they want to know about how clients perceive their program. The PES should become a useful tool both for researchers interested in how client responses to programs may influence their therapeutic outcomes, and for practitioners interested in improving their clients' program experiences and/or increasing convergence of staff and client views of their program.     

Neuropsychological Evaluation of Everyday Memory

The evaluation of everyday memory (EM) was reviewed and reconceptualized. EM has established new objectives of study and the development of new methods to reach these objectives . At the basic level, this approach has already produced important discoveries and the development of new principles about memory and functioning. At the clinical level, this new area of investigation has resulted in evaluating deficits of EM, which is defined as what daily life functions remain impaired after a deficit pathology has occurred. A type of evaluation has evolved that is oriented toward treatment and extremely useful in designing rehabilitation programs for individuals with alterations in memory.     

PROGRAMMING FOR SURVIVAL: A MEETING SYSTEM THAT SURVIVES 8 YEARS LATER

Effective and useful interventions often deteriorate when researchers withdraw their direct supervision. We tested the survival of an intervention designed to produce effective weekly meetings in a student housing cooperative without direct researcher supervision. Chairperson performance, proposals completed per hour, and ratings of chairperson performance all increased when resident staff used a training manual, prompting checklist, and performance reviews. Eight years of follow-up revealed continuing high levels of meeting effectiveness. This study demonstrates a methodology for the direct observation and experimental analysis of intervention survival.     

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.     

Tests of sphericity of normal distributions and the analysis of repeated measures designs

The locally best invariant test statistic for testing sphericity of normal distributions is shown to be a simple function of the Box/Geisser-Greenhouse degrees of freedom correction factor in a repeated measures design. Because of this relationship it provides a more intuitively appealing test of the necessary and sufficient conditions for valid F-tests in repeated measures analysis of variance than the likelihood ratio test. The properties of the two tests are compared and tables of the critical values of the Box/Geisser-Greenhouse correction factor are given.     

Test theory without true scores?

This paper traces the course of the consequences of viewing test responses as simply providing dichotomous data concerning ordinal relations. It begins by proposing that the score matrix is best considered to be items-plus-persons by items-plus-persons, and recording the wrongs as well as the rights. This shows how an underlying order is defined, and was used to provide the basis for a tailored testing procedure. It also was used to define a number of measures of test consistency. Test items provide person dominance relations, and the relations provided by one item can be in one of three relations with a second one: redundant, contradictory, or unique. Summary statistics concerning the number of relations of each kind are easy to get and provide useful information about the test, information which is related to but different from the usual statistics. These concepts can be extended to form the basis of a test theory which is based on ordinal statistics and frequency counts and which invokes the concept of true scores only in a limited sense.1979 Psychometric Society presidential address.I want to recognize the contributions which others have made to whatever I have accomplished. First to mention here are my teachers: principally Harold Gulliksen, Ledyard Tucker, and the late Edith Jay. Second, I would like to recognize the importance of my graduate students. Tom Reynolds has been especially important in developing the ideas that I will talk about here today, but at various times, the others have made major contributions in this and other topics. I would like to express also a debt to my family, primarily my wife, Rosemary, who herself has a longterm interest in the psychometric area. Finally, I must acknowledge the financial support of the NIMH some time ago, the Office of Naval Research, until about a year ago, and of the James McKeen Cattell Fund this past year.     

An implicit technology of generalization

Traditionally, discrimination has been understood as an active process, and a technology of its procedures has been developed and practiced extensively. Generalization, by contrast, has been considered the natural result of failing to practice a discrimination technology adequately, and thus has remained a passive concept almost devoid of a technology. But, generalization is equally deserving of an active conceptualization and technology. This review summarizes the structure of the generalization literature and its implicit embryonic technology, categorizing studies designed to assess or program generalization according to nine general headings: Train and Hope; Sequential Modification; Introduce to Natural Maintaining Contingencies; Train Sufficient Exemplars; Train Loosely; Use Indiscriminable Contingencies; Program Common Stimuli; Mediate Generalization; and Train "To Generalize".