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Results for “External validity”

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At least 1,135 records · Page 63Linked to original sources
PubMed1997

Schizotypy in community samples: the three-factor structure and correlation with sustained attention.

The authors examined cross-cultural applicability of the Schizotypal Personality Questionnaire (SPQ), the Perceptual Aberration Scale (PAS), and the Continuous Performance Test in community samples of Taiwanese adults and adolescents. The authors tested hypotheses that a 3-factor structure of the SPQ (Cognitive-Perceptual, Interpersonal, and Disorganization: A. Raine et al., 1994) exists for both samples and that the Interpersonal factor is associated with poorer attention. The authors replicated the 3-factor model for both samples, and they externally validated the model in adults: The Interpersonal factor and possibly the Disorganization factor were associated with poorer attention, whereas the Cognitive-Perceptual factor was not. The PAS differed from the Cognitive-Perceptual factor in its consistent association with poorer attention in both samples. These have important implications for the scales in the early detection of the schizotypy in various cultures.

Adolescent↗
PubMed1993

An appraisal of rational-emotive therapy.

Albert Ellis's rational-emotive therapy (RET) is scrutinized on several conceptual and empirical grounds, including its reliance on constructive assessment and its ethical stance. Its professional impact thus far exceeds its scientific status. Opinion varies on how even to define irrational beliefs; 1 consequence is problems in assessing them. Meta-analytic reviews provide support for the general utility of RET, but more qualitative reviews question both the internal and external validity of much of the published research. Lacking are process studies that can shed light on the mechanisms of therapeutic change, a situation likely due to the complexity of RET and to a lack of consensus as well about its very definition. Perhaps more progress can be achieved by forsaking studies of RET as a package and shifting instead to examination of specific therapeutic tactics in particular circumstances.

Adaptation, Psychological↗
PubMed1994

Can treatment research inform decision makers? Nonexperimental method issues and examples among older outpatients.

Outcome research does not seem to have informed policymakers, decision makers, or practitioners. It is proposed that reporting of improvement-deterioration rates and greater use of single-sample, pretreatment-posttreatment designs in community clinic settings will facilitate communication and, perhaps, mitigate the external validity problem of psychotherapy experiments. The Edwards-Nunnally method (D. C. Speer, 1992) was used to investigate change rates from a single cohort of older adult outpatients (N = 92). The cohort improvement rate was 51%, and the deterioration rate was 5%. However, improvement rates for clients with major depression and adjustment disorders were greater than 70%. Change rates of student and staff therapists and of clients treated in the clinic and in their homes were not significantly different. Deteriorated clients are briefly described.

Adjustment Disorders↗
PubMed1999

Caveats concerning comparisons of change rates obtained with five methods of identifying significant client changes: comment on Speer and Greenbaum (1995).

Various methods have been proposed to identify clients who have improved, have not changed, or have deteriorated in psychotherapy. D. D. Speer and P. E. Greenbaum (1995) compared empirically determined change rates (proportions of clients identified as improved, unchanged, or deteriorated) obtained with 5 of these methods, tested the hypothesis that 1 method would be more sensitive than the other 4 in detecting significant changes, and recommended 2 of the 5 methods. This comment draws attention to problems related to the meaning of their comparisons of change rates and to some implications of their recommendations. These problems include misinterpretation of formulas; use of methods with questionable standard errors; confounding of effects of methods with effects of norms, data sets, and risks of misclassifying patients who do not change; absence of valid external criteria of client changes; and excessive reliance on the Jacobson-Truax method for evaluation of 2-wave data.

Humans↗
PubMed2002

Motivated decision making: effects of activation and self-centrality of values on choices and behavior.

Six studies examined the value-behavior relation and focused on motivational properties of values, the self, and value activation. Priming environmental values enhanced attention to and the weight of information related to those values, which resulted in environmentally friendly consumer choices. This only occurred if these values were central to the self-concept. Value-congruent choices were also found in response to countervalue behavior in an unrelated context. Donating behavior congruent with central altruistic values was found as a result of enhanced self-focus, thus demonstrating the importance of the self in the value-behavior relation. The external validity of the value-centrality measure and its distinction from attitudes were demonstrated in the prediction of voting. Values were thus found to give meaning to, energize, and regulate value-congruent behavior, but only if values were cognitively activated and central to the self.

Analysis of Variance↗
PubMed1999

Heroin addicts have higher discount rates for delayed rewards than non-drug-using controls.

Fifty-six heroin addicts and 60 age-matched controls were offered choices between monetary rewards ($11-$80) available immediately and larger rewards ($25-$85) available after delays ranging from 1 week to 6 months. Participants had a 1-in-6 chance of winning a reward that they chose on one randomly selected trial. Delay-discounting rates were estimated from the pattern of participants' choices. The discounting model of impulsiveness (Ainslie, 1975) implies that delay-discounting rates are positively correlated with impulsiveness. On average, heroin addicts' discount rates were twice those of controls (p = .004), and discount rates were positively correlated with impulsivity as measured by self-report questionnaires (p < .05). The results lend external validity to the delay-discounting rate as a measure of impulsiveness, a characteristic associated with substance abuse.

Adult↗
PubMed1987

Impact of symptoms and aging attribution on emotions and coping.

Two experimental studies and a large field study were designed to examine how symptom severity, symptom duration, symptom ambiguity, and the association of symptoms with aging affected emotional responses and coping with illness threats. In Study 1, 280 respondents from the surrounding community reported the emotional and coping responses they would manifest to scenarios that varied the severity, duration, and ambiguity (i.e., labeled vs. unlabeled) of a common set of symptoms. Severity had more of an impact on coping strategies than did duration or illness label; severe symptoms elicited stronger emotional upset and a higher incidence of both self-care behaviors and seeking of medical care. Symptoms of longer duration also resulted in increased seeking of medical care. Responses of the 334 adults participating in Study 2 replicated and extended these findings: A closed-ended item asking participants whether the symptoms could be attributed to aging showed that attribution of symptoms to aging increased with age, was more frequent for mild symptoms, and was associated with reduced emotional response to symptoms and a tendency to delay seeking treatment. Participants in the field study (168 patients seeking medical care for a variety of symptoms) completed interviews tracing symptom processing and emotional and coping reactions. The results provided evidence for the external validity of the scenario studies, as the attribution of symptoms to aging was greater for older than younger patients and resulted in a significant tendency to delay seeking medical care. Results of these studies suggest that symptom experience and symptom interpretation must be considered in the study of coping responses to illness threats.

Adaptation, Psychological↗
PubMed1998

A molar entropy model of age differences in spatial memory.

Two very-short-term-memory, spatial scanning aging experiments were conducted involving a graphics character as a target stimulus. On the probe portion of a trial, the stimulus was presented in the same position as it was on the target portion of the trial (i.e., a same trial) 50% of the time. However, on the remaining 50% of the trials, the probe stimulus was shifted (or transposed) 1, 2, or 3 positions to the right or left of the original presentation (target) position. In Experiment 1, exposure duration was manipulated. In Experiment 2, the number of potential target display positions was manipulated. For both experiments, older adults showed larger transposition distance effects than younger adults for errors. In the past (e.g., P.A. Allen, 1990, 1991), this effect has been attributed to higher levels of internal noise (entropy) in older than younger adults. This research provides converging operations to this contention by using statistical physics methods to rigorously compute the entropy in a molar neural network across age groups. After successfully fitting the statistical mechanics model to the data, the model is proved to have external validity by fitting a simplified version of it to an earlier spatial memory aging experiment reported by P. R. Bruce and J. F. Herman (1986). The results of both traditional reaction time and error rate analyses, as well as the entropy modeling analyses, indicated that older adults exhibited higher levels of entropy than did the younger adults and that this effect appeared to be generalized across processing stage.

Adolescent↗
PubMed1991

How general is general slowing? Evidence from the lexical domain.

Three analyses are reported that are based on data from 19 studies using lexical tasks and a reduced version of the Hale, Myerson, and Wagstaff (1987) nonlexical data set. The results of Analysis 1 revealed that a linear function with a slope of approximately 1.5 described the relationship between the lexical decision latencies of older (65-75 years) and younger (19-29 years) adults. The results of Analysis 2, based on response latencies from 6 lexical tasks other than lexical decision, revealed a virtually identical linear relationship. In Analysis 3, it was found that performance on nonlexical tasks spanning the same range of task difficulty was described by a significantly steeper regression line with a slope of approximately 2.0. These findings suggest that although general cognitive slowing is observed in both domains, the degree of slowing is significantly greater in the nonlexical domain than in the lexical domain. In addition, these analyses demonstrate how the meta-analytic approach may be used to determine the limits to the external validity of experimental findings.

Adult↗
PubMed2005

In the eye of the storm: race and genomics in research and practice.

The difficulties of operationalizing race in research and practice for social, behavioral, and genetic researchers and practitioners are neither new nor related to recent genetic knowledge. For geneticists, the bases for understanding groups are clines, observed traits that gradually change in frequency between geographic regions without distinct identifiable population boundaries and population histories that carry information about the distribution of genetic variants. For psychologists, race may not exist or be a social and cultural construct associated with fluid social inferences. Because definitions of populations and race can be socially and biologically incongruent, the authors suggest that geneticists and social and behavioral scientists and clinicians attend to external validity issues by operationalizing population and racial categories and avoiding race proxies for other biological, social, and cultural constructs in research designs, data analyses, and clinical practice.

Clinical Trials as Topic↗
PubMed2004

The structure of child and adolescent psychopathology: generating new hypotheses.

To begin to resolve conflicts among current competing taxonomies of child and adolescent psychopathology, the authors developed an interview covering the symptoms of anxiety, depression, inattention, and disruptive behavior used in the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994), the International Statistical Classification of Diseases and Related Health Problems (ICD-10; World Health Organization, 1992), and several implicit taxonomies. This interview will be used in the future to compare the internal and external validity of alternative taxonomies. To provide an informative framework for future hypothesis-testing studies, the authors used principal factor analysis to induce new testable hypotheses regarding the structure of this item pool in a representative sample of 1,358 children and adolescents ranging in age from 4 to 17 years. The resulting hypotheses differed from the DSM-IV, particularly in suggesting that some anxiety symptoms are part of the same syndrome as depression, whereas separation anxiety, fears, and compulsions constitute a separate anxiety dimension.

Adolescent↗
PubMed2003

Comparison of embedded and isolated administrations of the California Psychological Inventory's Socialization subscale.

Alternate administration methods were tested for the Socialization (So) subscale of the California Psychological Inventory (CPI; H. G. Gough, 1994; H. G. Gough & P. Bradley, 1996) in 437 young adult men. One method administered the 46 CPI-So items in isolation from the CPI, whereas the 2nd method administered the 46 items embedded in the CPI. External validity measures of antisociality were also administered over the 2 sessions. Isolated administration produced somewhat higher internal consistency and significantly better concurrent validity and demonstrated construct validity as a measure of antisociality. Additional factor analytic studies of the CPI-So and CPI revealed that the 2 CPI-So versions had different factorial structures and that the embedded CPI-So subscale did not retain factorial integrity or an appreciable amount of reliable and uniquely interpretable variance.

Adult↗
PubMed2004

The effect of attribute order on judgment in Chinese and English.

The authors found that the order of attribute presentation had a stronger effect on judgment in English than in Chinese. In Experiment 1, with a sample of 102 female and 63 male bilingual Singaporeans, the authors found that participants' memory-based judgments showed a stronger primacy effect in English than in Chinese that was mediated by recall from long-term memory. In contrast, participants' online (immediate) judgments showed a primacy effect in both languages that was unmediated by recall from short-term memory. In Experiment 2, with a sample of 67 female and 53 male bilingual Singaporeans, the authors found that participants' online judgments were more influenced by the attribute order of a previously seen competitive advertisement in English than in Chinese. A cross-cultural field study in Mainland China and the United Kingdom provided external validity for the experimental results.

Adolescent↗
PubMed2006

Paper and plastic in daily diary research: Comment on Green, Rafaeli, Bolger, Shrout, and Reis (2006).

The authors applaud A. S. Green, E. Rafaeli, N. Bolger, P. E. Shrout, and H. T. Reis's (2006) response to one-sided comparisons of paper versus electronic (plastic) diary methods and hope that it will stimulate more balanced considerations of the issues involved. The authors begin by highlighting areas of agreement and disagreement with Green et al. The authors review briefly the broader literature that has compared paper and plastic diaries, noting how recent comparisons have relied on study designs and methods that favor investigators' allegiances. The authors note some sorely needed data for the evaluation of the implications of paper versus plastic for the internal and external validity of research. To facilitate evaluation of the existing literature and assist in the design of future studies, the authors offer a balanced comparison of paper and electronic diary methods across a range of applications. Finally, the authors propose 2 study designs that offer fair comparisons of paper and plastic diary methods.

Adolescent↗
PubMed2002

Revisiting field experimentation: field notes for the future.

Field experiments in the social sciences were increasingly used in the 20th century. This article briefly reviews some important lessons in design, analysis, and theory of field experiments emerging from that experience. Topics include the importance of ensuring that selection into experiments and assignment to conditions occurs properly, how to prevent and analyze attrition, the need to attend to power and effect size, how to measure and take partial treatment implementation into account in analyses, modern analyses of quasi-experimental and multilevel data, Rubin's model, and the role of internal and external validity. The article ends with observations on the computer revolution in methodology and statistics, convergences in theory and methods across disciplines, the need for an empirical program of methodological research, the key problem of selection bias, and the inevitability of increased specialization in field experimentation in the years to come.

Forecasting↗
PubMed2001

Prediction of body fat by anthropometry in older Chinese people.

OBJECTIVE: To derive regression equations for fat percentage by using simple anthropometric measurements applicable in normal and immobile (cannot stand or walk) older people. RESEARCH METHODS AND PROCEDURES: The study population comprised 352 females and 261 males, apparently well and community-dwelling, aged 69 to 82 years. Fifty-one females and 27 males were recruited for external validation. Body weight, standing height, arm span, triceps and biceps skinfold thicknesses (SFTs), and midarm circumference were measured. The reference method of total body fat percentage was dual-energy X-ray densitometry. Predictive equations for fat percentages were derived by stepwise multiple linear regression on anthropometric indices and gender. RESULTS: Upper-limb SFTs, body mass index, and gender yielded the more predictive equation. The SEE was 4.1% weight. There was a significant trend of underestimation in overweight subjects, especially in females. The equation using SFTs and midarm circumference was less reliable but more applicable to older immobile people and those with significant kyphoscoliosis. CONCLUSIONS: The combination of body mass index and upper-limb SFTs gives reliable prediction of fat percentages in older Chinese people, except in the obese.

Absorptiometry, Photon↗
PubMed2026

Consensus meta-analysis of genome-wide association studies for Alzheimer's disease and related dementias.

To better characterize the genetic architecture underlying Alzheimer's disease (AD) and related dementias (ADRD), we performed a meta-analysis of European-ancestry genome-wide association studies in 128,681 cases or proxy cases of ADRD and 849,833 (proxy) controls. We identified 91 genetic loci associated with ADRD risk, of which 16 are new and 56 are specifically detected in clinically diagnosed AD cases. We also provide a list of 18 loci (15 new) requiring further external validation. A polygenic score combining the effects of ADRD loci other than APOE was primarily associated with AD rather than non-AD pathology. Individuals in the tenth decile of the score exhibited a twofold increased risk of presenting with Braak neurofibrillary tangles stage of >4 and moderate-to-severe neuritic amyloid plaque pathology at death compared to individuals in the median score group. In conclusion, our study validated a large number of loci associated with the risk of clinically diagnosed AD, while further investigations are required to confirm the impact of the other loci on AD clinical diagnosis and of each locus on AD pathology.

Humans↗
PubMed1995

Lumbar spinal stenosis causing intermittent priapism.

The current report concerns the unusual symptom of intermittent priapism, or what may be termed 'involuntary penile erection', associated with proven degenerative lumbar spinal stenosis. Seven patients who were treated for intermittent claudication and spontaneous priapism during walking were studied in terms of clinical presentation, imaging findings, and some electrophysiological testing. Varying degrees of walking and standing tolerance with these unusual symptoms appeared to be correlated with cauda equina constriction as was seen by radiological imaging. Although not statistically valid, external urethral sphincter evoked electromyography suggested the possibility of monitoring the unusual symptom during walking. Surgical spinal decompression is recommended to alleviate this symptom and the claudication.

Aged↗