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PubMed2005

Beginning with the application in mind: designing and planning health behavior change interventions to enhance dissemination.

Failing to retain an adequate number of study participants in behavioral intervention trials poses a threat to interpretation of study results and its external validity. This qualitative investigation describes the retention strategies promoted by the recruitment and retention committee of the Behavior Change Consortium, a group of 15 university-based sites funded by the National Institutes of Health to implement studies targeted toward disease prevention through behavior change. During biannual meetings, focus groups were conducted with all sites to determine barriers encountered in retaining study participants and strategies employed to address these barriers. All of the retention strategies reported were combined into 8 thematic retention categories. Those categories perceived to be most effective for retaining study participants were summarized and consistencies noted among site populations across the life course (e.g., older adults, adults, children, and adolescents). Further, possible discrepancies between site populations of varying health statuses are discussed, and an ecological framework is proposed for use in future investigations on retention.

Behavior Therapy↗

PubMed2005

Strategies for retaining study participants in behavioral intervention trials: retention experiences of the NIH Behavior Change Consortium.

Health Behavior↗

PubMed1991

A confederate's perspective on deception.

In this article, I outline my position regarding the use of deception in psychology experiments, based on my experience as a confederate. I describe an experiment I participated in and the problems resulting from the study: subjects' differing responses to the deception; angry reactions of some subjects to the experiment; and the general discomfort of both the subjects and the confederates, in particular, who had their doubts concerning the external validity of the study and the ethics involved in running it. Issues of informed consent and debriefing are also addressed; it is argued that the success of deception depends on the subject being misinformed as to the experiment's true nature and that debriefing itself sometimes angers subjects. I encourage a decrease in the use of deception and the reexamination of a system that attempts to balance the pain of experimental participants with anticipated benefit to scientific knowledge.

Behavioral Research↗

PubMed2006

Understanding exercise behavior among Korean adults: a test of the transtheoretical model.

The purpose of this study was to examine the theorized association of Transtheoretical Model (TTM) of behavior change constructs by stage of change for exercise behavior among Korean adults. A total of 1,335 Korean adults were recruited and surveyed from the Nowon district, geographically located in northern Seoul. Four Korean-version questionnaires were used to identify the stage of exercise behavior and psychological attributes of adolescents. Data were analyzed by frequency analysis, MANOVA, correlation analysis, and discriminant analysis. Multivariate F tests indicated that behavioral and cognitive processes of change, exercise efficacy, and pros differentiated participants across the stages of exercise behavior. Furthermore, the findings revealed that adults' exercise behavior was significantly correlated with the TTM constructs and that overall classification accuracy across the stages of change was 50.6%. This study supports the internal and external validity of the TTM for explaining exercise behavior.

Adult↗

PubMed1983

Personality structure of Mexican Americans using the Comrey Personality Scales.

The Comrey Personality Scales (CPS) were used to examine the personality structure of 176 Mexican American college students. A majority of the eight factors maintained substantial loadings and corresponded closely with Comrey's normative sample as well as with Brazilian and New Zealand samples. Two factors, Conformity and Orderliness, showed the weakest fit across all four groups. Overall, the CPS shows adequate measurement properties for "normal" personality assessment among Mexican Americans and is preferable to instruments such as the Minnesota Multiphasic Personality Inventory (MMPI). However, the external validity of the CPS with clinical populations must first be determined prior to its use to assess psychopathology among Mexican Americans.

Journal Article↗

PubMed1991

Three methods of developing MMPI taxonomies of sexual offenders.

In a sample of 261 state hospital sexual offenders, Minnesota Multiphasic Personality Inventory (MMPI) profiles did not differ for offenders with adult victims versus offenders with child victims when offender age was controlled. MMPI 2-point analyses for the whole sample revealed five common codes that were independent of victim maturity. The sample was randomly divided in half and subjected to a cluster-analytic procedure which revealed two MMPI clusters. The first cluster was unelevated, with Scale 4 as its high point. The second cluster had multiple elevations, with Scales 8, 4, 2, and 7 as the highest scales. These clusters were replicated in a cluster analysis of the second half of the sample. However, when the sample was recombined, the two clusters were not externally validated basis on demographic and criminological variables. The results suggest that common psychological variables among sexual offenders may have more discriminative value than victim maturity in developing sexual offender taxonomies.

Adult↗

PubMed2000

Assessing achievement, affiliation, and power motives all at once: the Multi-Motive Grid (MMG).

In this article, we introduce the Multi-Motive Grid (MMG), a new diagnostic tool to measure motives with respect to their hope and fear components. The MMG combines features of the Thematic Apperception Test (TAT) with features of self-report questionnaires. Similar to the TAT, a set of 14 pictures representing a balanced set of achievement-arousing, affiliation-arousing, and power-arousing situations is presented together with a set of statements representing important motivational states. Six motive scores can be calculated: hope of success (HS) and fear of failure (FF) for the achievement motive, hope of affiliation (HA) and fear of rejection (FR) for the affiliation motive, and hope of power (HP) and fear of power (FP) for the power motive. Results of factor analyses suggest a 3-factor solution, with a general fear factor (FF, FR, FP), a factor combining the hope components of achievement and power (HS and HP), and a third factor representing HA, but the 6 a priori factors also reflect a sound structural model. Reliability data show that the internal consistency and retest reliability of the MMG scales satisfy traditional standards. External validity of the MMG has been established in all 3 motive domains. Three separate studies document that (a) individuals high in resultant achievement motivation perform better and report more flow experience, (b) individuals high in resultant power motivation profit more from a leadership training program, and (c) individuals high in resultant affiliation motivation recollect more highly memorable affiliative themes.

Achievement↗

PubMed1997

Levels of analysis and the explanation of the costs and benefits of cooperation.

In this article we contrast static and dynamic theories of the effects of increasing the costs and benefits of cooperation in a repeated play prisoners' dilemma (PD). Using computer simulation as the methodology, we show that different decision heuristics respond differently to changes in the cost-benefit structure of a PD game, an effect not expected by static theories of cooperation. In addition, one of the heuristics, "win-stay, lose-change,"" displays the pattern of cooperation predicted by static theories, but the underlying mechanisms are qualitatively different from those assumed in the static theory. This demonstration raises questions about the external validity of the different types of social psychological theory.

Journal Article↗

PubMed2004

Factors influencing the exercise behavior of adults with physical disabilities.

PURPOSE: Examine the theorized associations of transtheoretical model (TTM) of behavior change constructs (behavioral and cognitive processes of change, decisional balance, and self-efficacy), along with exercise barriers, by stage of change for exercise behavior among individuals with physical disabilities. METHODS: Cross-sectional survey of 322 adults with physical disabilities residing in the United States. Most participants (84.3%) used some form of assistive device (e.g., artificial limb, wheelchair), were female (62.1%), and Caucasian (91.9%). The mean age of participants was 52.5 yr (SD = 13.9). Participants completed and returned questionnaires for each TTM construct, along with an exercise barriers measure. RESULTS: In univariate analyses, all constructs were significantly (P < 0.001) associated with the stages of change for exercise behavior, except for dramatic relief (P > 0.005). The largest portion of variance was derived from counter conditioning (eta = 0.45), followed by the five behavioral processes of change combined (eta = 0.40), self-liberation (eta = 0.31), self-efficacy (eta = 0.30), and self-reevaluation (eta = 0.28). Direct discriminant function (multivariate) analysis revealed four discriminant functions which accounted for 71.0% (P < 0.001), 20.9% (P < 0.001), 6.3% (P < 0.05), and 1.8% (P = 0.62), respectively, of the between-group (stage of change) variability. The overall stage of change classification accuracy was 70.8%. CONCLUSION: This was the first study to examine the stages of change for exercise behavior among adults with physical disabilities on the basis of the full TTM and exercise barriers. Overall, the results are in general agreement with existing evidence among nondisabled populations. This provides further cross-sectional support for the internal and external validity of TTM and exercise barriers among a unique and understudied population segment.

Adult↗

PubMed2005

Using pharmacy data to identify those with chronic conditions in Emilia Romagna, Italy.

BACKGROUND AND OBJECTIVES: Automated pharmacy data have been used to develop a measure of chronic disease status in the general population. The objectives of this project were to refine and apply a model of chronic disease identification using Italian automated pharmacy data; to describe how this model may identify patterns of morbidity in Emilia Romagna, a large Italian region; and to compare estimated prevalence rates using pharmacy data with those available from a 2000 Emilia Romagna disease surveillance study. METHODS: Using the Chronic Disease Score, a list of chronic conditions related to the consumption of drugs under the Italian pharmaceutical dispensing system was created. Clinical review identified medication classes within the Italian National Therapeutic Formulary that were linked to the management of each chronic condition. Algorithms were then tested on pharmaceutical claims data from Emilia Romagna for 2001 to verify the applicability of the classification scheme. RESULTS: Thirty-one chronic condition drug groups (CCDGs) were identified. Applying the model to the pharmacy data, approximately 1.5 million individuals (37.1%) of the population were identified as having one or more of the 31 CCDGs. The 31 CCDGs accounted for 77% (E556 million) of 2001 pharmaceutical expenditures. Cardiovascular diseases, rheumatological conditions, chronic respiratory illness, gastrointestinal diseases and psychiatric diseases were the most frequent chronic conditions. External validation comparing rates of the diseases found through using pharmacy data with those of a 2000 Emilia Romagna disease surveillance study showed similar prevalence of illness. CONCLUSIONS: Using Italian automated pharmacy data, a measure of population-based chronic disease status was developed. Applying the model to pharmaceutical claims from Emilia Romagna 2001, a large proportion of the population was identified as having chronic conditions. Pharmacy data may be a valuable alternative to survey data to assess the extent to which large populations are affected by chronic conditions.

Chronic Disease↗

PubMedDate not supplied

The confidence profile method: a Bayesian method for assessing health technologies.

The Confidence Profile Method is a Bayesian method for adjusting and combining pieces of evidence to estimate parameters, such as the effect of health technologies on health outcomes. The information in each piece of evidence is captured in a likelihood function that gives the likelihood of the observed results of the evidence as a function of possible values of the parameter. A posterior distribution is calculated from Bayes formula as the product of the likelihood function and a prior distribution. Multiple pieces of evidence are incorporated by successive applications of Bayes' formula. Pieces of evidence are adjusted for biases to internal or external validity by modeling the biases and deriving "adjusted" likelihood functions that incorporate the models. Likelihood functions have been derived for one-, two- and multi-arm prospective studies; 2 x 2, 2 x n and matched case-control studies, and cross-sectional studies. Biases that can be incorporated in likelihood functions include crossover in controlled trials, error in measurement outcomes, patient selection biases, differences in technologies, and differences in length of follow-up. Effect measures include differences of rates, ratios of rates, and odds ratios. The elements of the method are illustrated with an analysis of the effect of a thrombolytic agent on the difference in probability of 1-year survival after a heart attack.

Bayes Theorem↗

PubMed2001

A case-control study of differences between regular and causal adult attenders in general dental practice.

OBJECTIVES: To assess whether adults attending a dental practice for regular dental care have better oral health than adults attending casually in response to a dental problem, and to explore the barriers to asymptomatic attendance. METHODS: An observational case-control study comparing the characteristics of 100 regular attenders with 100 causal attenders in one general dental practice in North Staffordshire. All study subjects were aged 18 years or over. Sociodemographic characteristics of the two groups were collated, including age, gender, social class, marital status, employment status and smoking status. The primary outcome measure was the observed number of teeth with dentinal caries diagnosed using bitewing radiographs. RESULTS: Regular attenders were observed to have better oral health with respect to dental caries and tooth mobility (p < 0.05). This was not explained by the observation that causal attenders were more likely than regular attenders to be male, aged 18-44 years, in social class III or IV. Secondary outcomes, including number of subjects with mobile teeth and teeth with > 30% bone-loss, were also significantly worse in the casual attenders. However, the median number of teeth present in both groups was 27. In regular attenders, the most common reason for attending was to 'keep the teeth' (96%). In casual attenders, 'fear/dislike of dental treatment' was the most frequent indicator of non-attendance (56%). CONCLUSIONS: In our study, adults who regularly attended general dental practice were shown to have better oral health, including less overall tooth decay, mobility and bone-loss, compared with adults who did not attend on a regular basis. Assuming this result to be externally valid, a challenge for the dental profession in the future will be to develop effective oral health promotion initiatives.

Adolescent↗

PubMed1999

The impact of pharmaceutical services in community and ambulatory care settings: evidence and recommendations for future research.

OBJECTIVE: To review and evaluate research on pharmaceutical services in community and ambulatory care pharmacy settings, specifically study designs and patient outcome measures, and to provide recommendations to improve future research on pharmaceutical services in community and ambulatory care pharmacy settings. DATA SOURCE: English-language articles were identified by searching MEDLINE (1966-December 1998) and International Pharmaceutical Abstracts (1970-December 1998), using a combination of search terms: pharmacist services, pharmacist interventions, community pharmacy, ambulatory care, primary care, and patient outcomes. Relevant studies were selected based on article abstracts. DATA EXTRACTION: From each relevant study, we extracted the study objectives, sample size, study period, study design, major tasks performed by pharmacists, and economic, clinical, and humanistic outcomes (ECHO). Results were tabulated separately for research on community pharmacy and ambulatory care pharmacy settings. RESULTS: We identified 95 relevant studies. Of these, 21 studies were conducted in community pharmacy settings and 74 in ambulatory care settings. Ten community pharmacy studies used prospective, single group, pretest/posttest, or posttest only designs; seven used prospective two or more group comparison designs; and four used randomized, controlled designs. Nine studies on community pharmacies measured clinical outcomes, two measured humanistic outcomes, and five measured economic outcomes. Four studies measured both clinical and humanistic outcomes and one measured humanistic and economic outcomes. No study measured all three ECHO variables. Twenty-three studies in ambulatory care settings used prospective or retrospective, single group, pretest/posttest or posttest only designs; 21 used prospective or retrospective two-or-more group comparison designs; and 30 used randomized, controlled designs. Thirty-six measured clinical outcomes, five measured humanistic outcomes, and 15 measured economic outcomes. Fifteen studies measured clinical and economic outcomes and three measured clinical and humanistic outcomes. CONCLUSIONS: Only 21 of 95 selected studies were conducted in community pharmacy settings and measured the impact of pharmaceutical services on patient outcomes. Few studies employed adequate research designs to control threats to internal and external validity. In order to obtain a comprehensive and accurate picture of the impact of pharmaceutical services on patient outcomes, an attempt must be made to measure all three ECHO variables while employing adequate research design.

Ambulatory Care↗

PubMed2003

Pure and guided self-help for full and sub-threshold bulimia nervosa and binge eating disorder.

OBJECTIVE: The study compared the efficacy of self-help without and with guidance (referred to as 'pure' and 'guided' self-help), using a cognitive behavioral self-help manual (Fairburn, 1995) for binge eating. DESIGN AND METHODS: A sample of 31 participants with bulimia nervosa, subthreshold bulimia nervosa and binge-eating disorder were assigned randomly to one of the self-help levels for 16 weeks, after four weeks of baseline observations. RESULTS: The results indicated that both forms of self-help treatments had a modestly positive and sustained effect on the participants' eating problems. Intention-to-treat analyses showed that participants reduced their mean number of objective bulimic episodes and purging behaviour by 33% and 17% over the course of the treatment. The corresponding reduction levels for the treatment completers (N = 18) were 58% and 61%, respectively. Furthermore, there were no significant differences between the pure and guided self-help groups in terms of outcome, reflecting the probable insignificance of guidance for the broader group of individuals with binge-eating problems. At follow-up, no further significant improvement or deterioration was observed in the ensuing six months compared with the post-treatment data. CONCLUSION: Given the heterogeneity of the diagnostic groups in the present study, resulting in high external validity, and the conservative nature of the analyses, self-help is discussed as a viable means of initial treatment for binge eating.

Adult↗

PubMed2005

Remarks on the analysis of causal relationships in population research.

The problem of determining cause and effect is one of the oldest in the social sciences, where laboratory experimentation is generally not possible. This article provides a perspective on the analysis of causal relationships in population research that draws upon recent discussions of this issue in the field of economics. Within economics, thinking about causal estimation has shifted dramatically in the past decade toward a more pessimistic reading of what is possible and a retreat in the ambitiousness of claims of causal determination. In this article, the framework that underlies this conclusion is presented, the central identification problem is discussed in detail, and examples from the field of population research are given. Some of the more important aspects of this framework are related to the problem of the variability of causal effects for different individuals; the relationships among structural forms, reduced forms, and knowledge of mechanisms; the problem of internal versus external validity and the related issue of extrapolation; and the importance of theory and outside evidence.

Causality↗

PubMed2006

Optimization of discriminant partial least squares regression models for the detection of animal by-product meals in compound feedingstuffs by near-infrared spectroscopy.

This paper evaluates two multivariate strategies for classifying near-infrared (NIR) spectroscopic data for the detection of animal by-product meals (henceforth generically termed AbP) as an ingredient in compound feedingstuffs. Classification models were developed to discriminate between the presence and absence of animal-origin meals in compound feeds using two forms of discriminant partial least squares (PLS) regression: the algorithms PLS1 and PLS2. The training set comprised 433 commercial feeds, of which 148 contained AbP and the other 285 were stated to be AbP-free. Since the initial set contained unequal numbers of each class, the effect of this imbalance was analyzed by applying the same algorithms to a training set containing equal numbers of AbP-free and AbP-containing samples. The best classification model (97.42% of samples correctly classified), obtained with PLS2, that showed less sensitivity to the use of class-unbalanced sets, was externally validated using a set of 18 samples (10 AbP-containing and 8 AbP-free); all samples were correctly classified, except for one AbP-free sample that was classified as containing AbP (false positive). The results suggest that the application of PLS discriminant analysis to NIR spectroscopic data enables detection of AbP, a feed ingredient banned since the bovine spongiform encephalopathy (BSE) crisis; this confirms the value of NIRS qualitative analysis for product authentication purposes.

Algorithms↗

PubMed2025

Alterations in ether lipid metabolism in obesity revealed by systems genomics of multi-omics datasets.

Ratios between two metabolites are sensitive indicators of metabolic changes. Lipidomic profiling studies have revealed that plasma ether lipids, a class of glycero- and glycerophospho-lipids with reported health benefits, are negatively associated with obesity. Here, we utilized lipid ratios as surrogate markers of lipid metabolism to explore the processes underlying the inverse relationship between ether lipid metabolism and obesity. Plasma lipidomics data from two independent human cohorts (n = 10,339 and n = 4,492) were integrated to assess the associations between 82 lipid ratios and obesity-related markers in males and females. Results were externally validated using mouse transcriptomics data from the Hybrid Mouse Diversity Panel (n = 152-227 across 74 strains). Genome-wide association studies using imputed genotypes from a population cohort (n = 4,492) were performed to examine the genetic architecture of the ratios. Findings showed that waist circumference (WC), body mass index, and waist-hip ratio were inversely associated with total plasmalogens relative to total phospholipids in both sexes. Ratios comprising product-substrate pairs positioned either side of enzymes involved in plasmalogen synthesis and degradation showed positive and negative associations with WC, respectively. Branched-chain fatty acids negatively correlated with WC, while omega-6 polyunsaturated fatty acids exhibited differing associations depending on their position within the pathway. Mouse transcriptomics corroborated these results. Genomics data showed strong associations between ratios containing choline-plasmalogens and single-nucleotide polymorphisms in the transmembrane protein 229B (TMEM229B) gene region. This work demonstrates the utility of lipid ratios in understanding lipid metabolism. By applying the ratios to multi-omic datasets, we identified alterations in enzymatic activity and genetic variants likely affecting ether lipid synthesis in obesity that could not have been obtained from lipidomics data alone. Additionally, we characterized a potential role for TMEM229B, offering new perspectives on ether lipid metabolism and regulation.

Humans↗

PubMed2026

Graph neural network-based risk stratification of prostate cancer using gene expression and SHAP interpretability.

Accurate risk stratification is essential for guiding treatment decisions and preventing over treatment of prostate cancer, which remains one of the most prevalent cancers among adult men. While the Gleason score, obtained from prostate biopsies, is routinely used to assess tumor aggressiveness, the biopsy procedure carries risks such as pain, infection, and, in some cases, serious complications such as sepsis. In this study, we proposed an artificial intelligence-based framework that integrates mRNA expression profiles with functional interaction networks to classify prostate cancer patients into low-, medium-, and high-risk groups defined by Gleason scores. The pipeline comprised five steps: (1) data collection from The Cancer Genome Atlas (TCGA), (2) preprocessing of gene expression data, (3) two-stage feature selection to identify informative biomarkers, (4) risk classification using a dual-branch graph neural network (GNN) that combines gene-gene interaction graphs with sample-level expression features, and (5) model interpretation using SHAP to quantify feature contributions. Differentially expressed genes were identified in the High (ASPN, GMNN, PEBP4, C2, KNCK17), Medium (C2, IGSF1, ASPN, CDKN3, AMH), and Low (TNMD, VWA5B2, ST6GALNAC5, CYP3A5, PHGR1) risk groups, underscoring the molecular heterogeneity of disease progression. On an independent held-out test set, the model achieved AUCs of 0.86, 0.88, and 0.95 for the low-, medium-, and high-risk groups, respectively, with an overall accuracy of 80%. These results suggest that combining GNN-based modeling with explainable AI can capture both global and local molecular patterns relevant to tumor aggressiveness. However, as the model was developed and evaluated solely on the TCGA cohort, the findings should be regarded as exploratory, and external validation will be required to establish generalizability. Within these limitations, the proposed framework highlights the potential of molecular profiling and graph-based deep learning to support more precise, potentially less invasive, risk assessment and individualized treatment planning in prostate cancer.

Prostatic Neoplasms↗