Injury analysis and prevention in the developing countries.
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Biomedical subjects
Publications and source records attributed to S J Guastello.
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Catastrophe models, which describe and predict discontinuous changes in system state variables, were used to model the exposure to blood and bodily fluids and more conventional occupational accidents among 1708 health care workers. Workers at three hospitals completed a survey measuring HIV-relevant exposures (needlesticks, cuts, splashes, contact with open wounds), the accident rate for broadly-defined injuries, and several occupationally relevant themes: safety climate, shift work, depression symptoms, work pace, verbal abuse, and professional group membership. A cusp (cubic polynomial) model predicting HIV-relevant exposures specifically was more accurate (R2 = 0.56) than a comparable linear model containing the same variables (R2 = 0.07). Some of the foregoing variables predisposed workers to greater differences in HIV-relevant and general accident exposures: shiftwork, climate, depressive symptoms, and work pace. Other variables governed how close an individual was to a critical threshold where a harmful incident would take place: verbal abuse, professional group membership. Similarly, a cusp model for accident incidents predicted from HIV-relevant exposures and occupational variables was also more accurate (R2 = 0.75) than comparison models. Two variables predisposed the worker to a greater accident risk: depression symptoms and shift work. Four other variables predisposed the worker to lesser accident risk: job satisfaction, safety climate, environmental stressors, and work pace. Compliance with the universal precautions and HIV-related training were not relevant to either of the models.
This study is an attempt to delineate symptom clusters that may be considered most distinctive of patients diagnosed with borderline personality disorder (BPD). Medical records were examined to assess the extent to which each of the eight DSM-III-R BPD criteria was present in 89 psychiatric in-patients diagnosed with BPD. Structural analysis revealed three symptom clusters that can explain symptomatology for a majority of the sample. BPD patients can be identified initially by a core factor and separated subsequently into several BPD subtypes based on the patients' remaining symptomatology. A hierarchical diagnostic scheme for delineating BPD subtypes is proposed, and the implications of these findings for a theoretical separation of several BPD subtypes are discussed.
Three studies were conducted to assess the role of individual differences among raters participating in validation studies for computer-based test interpretations (CBTIs) and to assess the reliability of ratings. Studies centered on two CBTIs for the Sixteen Personality Factor Questionnaire (16PF). The first study involved 54 students who rated the accuracy of the Human Resource Development Report (HRDR) in an experimental context. The second study involved 73 students who rated the HRDR in a nonexperimental context. The third study involved 28 students who rated the Narrative Score Report (NSR) in a nonexperimental context. Results taken together indicate that (a) shrewdness may influence ratings of CBTI accuracy in an experimental context; (b) self-sufficiency, emotional stability, dominance, or abstract thought may influence ratings in a nonexperimental context, depending on the specific report involved: (c) test-retest reliabilities for accuracy ratings were .74 for HRDR and .81 for NSR; and (d) test-retest reliabilities for usefulness ratings were .75 for HRDR and .54 for NSR.
Meta-interpretive reliability is a new method to evaluate the accuracy with which personality trait scores are communicated via interpretive statements in a computer-based test interpretation (CBTI). The prototypic experimental design is based on a two-way repeated measures analysis of variance (ANOVA); the two effects are personality traits and randomly chosen CBTI protocols. In this application, 101 psychologists read four examples of the Karson Clinical Report (KCR, Karson & O'Dell, 1975) and estimated the original trait scores from the Sixteen Personality Factor Questionnaire (16PF; Cattell, Eber, & Tatsuoka, 1970) on which the KCR is based. Estimated trait score variance was significantly related to the Trait x Protocol interaction and the main effects for personality trait and differences among protocols (omega 2 = .55). The total effect size corresponded to a multiple correlation of .74, suggesting that the KCR had acceptable meta-interpretive reliability. The protocol effect denoted a context effect created by the juxtaposition of several interpretive statements. Additional analyses showed that individual differences among raters contributed to less than 1% of the estimated standard ten (sten) score variance. Meta-interpretive reliability is proposed as an index of the upper limit of validity for CBTIs.
Total scores of the Raven's Standard Progressive Matrices (SPM) were correlated with Wechsler Adult Intelligence Scale-Revised Full Scale IQs (WAIS-R FSIQ) in order to obtain age-stratified estimates of WAIS-R FSIQ (N = 308). Results show a significant positive correlation between age-stratified WAIS-R FSIQ and SPM in all age groups except those 65 and older and between educational level and SPM for all age groups except the very young (16 to 24 years), the 55- to 64-year-olds, and the elderly (65 and older). A multiple regression and cross-validation revealed that race and age also must be used as moderator variables when one is predicting FSIQ in this population. It is concluded that the SPM can be used as an estimate of WAIS-R FSIQ.
Twelve psychiatric outpatients were administered the Rorschach test, and results were interpreted using the Exner (1983, 1986) Report for the Comprehensive System computer-based test interpretation (CBTI) program. Four psychiatrists made accuracy ratings for both real and bogus reports for each of their patients. Data were analyzed using two-way analyses of covariance (ANCOVAs), where report type was a repeated main effect, psychiatrist was a random main effect, and the number of statements in the report was the covariate. Results indicated that this CBTI provided only 5% discriminating power for any one patient, with 60% of the interpretive statements merely describing typical characteristics of the outpatient population. No significant psychiatrist, interaction, or covariate effects were encountered.
The report details a catastrophe theory model of the accident process with empirical validation. According to the cusp model, two distinct levels of risk can be observed for a distribution of group accident rates, one at 0.0 Occupational Safety and Health Association (OSHA)-reportable accidents per 100 person-years of exposure and one at 11.5. Changes within or between the two levels are determined by two control parameters: environmental hazard (asymmetry) and operator load (bifurcation). The sample consisted of 68 work groups from 8 Milwaukee-Chicago area sheet metal mills and foundries who completed the Occupational Hazards Survey (OHS). The OHS contributed six bifurcation variables (safety management, life stress, physical stress anxiety, beliefs about accident control, and experience) and two asymmetry variables (environmental hazards and danger). All organizations received an interpretive report of their survey responses with recommendations for accident control, and had held their reports for two to nine months at the time the follow-up accident rate data were collected. There were two additional bifurcation variables: months holding report and group size. Regression analysis determined that the cusp model (R2 = .42) was more than twice as accurate as the best log-linear or linear alternative. Accidents were successfully controlled by safety managers' attention to recommendations produced by the OHS analysis. Catastrophe theory provided some novel insights regarding the linkage between predictor variables and actual behavior. Research has shown that a substantial percentage of occupational accidents are the result of human error. In an effort to explain and predict such errors in a systematic manner, an accident process model based on the cusp catastrophe is developed and tested. The model offers several unique and useful properties: (1) It proposes that changes in accident rates for work groups are the result of a nonlinear dynamic process. (2) The distribution of accident rates is bimodal, with one model near zero and the other at some higher level. (3) Changes in accident rates are predicted from four sources: (i) ambient danger and hazard levels, (ii) variables that impact upon human performance capability, (iii) initial accident rates, and (iv) the mathematical function that interrelates those variables. (4) The mathematical model has inherent properties that allow for causal inference. Environmental and human performance factors can be operationalized as sets of more specific variables. In this application. The Occupational Hazards Survey was used to gather data from mill and foundry workers pertaining to hazards and dangers, adequacy of safety management, stress, anxiety, and beliefs about accident control.(ABSTRACT TRUNCATED AT 400 WORDS)
This study examined a hypothesis first presented in the medical literature that persons who drink greater amounts of alcohol are more frequently involved in automobile accidents even though they were not under the influence of alcohol at the time of their accidents. Subjects were 130 undergraduates who contributed self-reports of automobile accidents in the preceding three years, near-miss accidents per week, and questionnaire measures of sociopathy, alcohol and drug use, and distortion (lie scale). No support was found for the alcohol hypothesis or a similar drug hypothesis. A very marginal link, however, was observed between accident involvement and sociopathic tendencies.
We investigated the relation between the Rotter (1966) locus of control concept and involvement in automobile accidents. Subjects were 184 college students who completed a survey measuring accident involvement, the Rotter scale, and scales featuring beliefs and behaviors in traffic situations that would be expected from internally oriented persons. No significant relation was found between the Rotter scale and traffic accidents. Accident involvement was best explained by internal beliefs about accident control, and the reported number of near-miss accidents per week. A path diagram relating survey variables is included.
This article studies human physical work capacity under increasing load from a general systems theory perspective. There are several points of generalization between the structure of nonliving (building materials) and living systems (humans) with respect to stress, strain, and fatigue. A catastrophe model for Euler buckling was transposed and tested for human performance in a wheelbarrow obstacle course under varying loads. Subjects were 129 employees of a Midwest manufacturing plant. A cusp model was hypothesized and verified (R2 = .68, control R2 = .11) where vertical load was the asymmetry factor, and body balance, height, and sex-related differences all contributed to bifurcation. A catastrophe model in codimension 10 was also invoked to explain memory in the system. Principal control variables were exercise habits, weight, balance, and sex-related differences (R2 = .75). The core model of human load-to-failure was concluded to be similar to that for Euler buckling: additional complexities were discovered which were attributed in part to systemic memory. Discussion points included the use of large dimension catastrophe models for problems involving complex lag effects, and the transposability of the model to the organizational systemic level.
This article considers a multilevel system problem involving color perception of individual human beings, man-machine interactions, and changing social factors. Previous research on the same system found critical differences in color matching performance over a 24-hour period, modeled by a cusp catastrophe. The hypothesis now tested is whether critical differences in group performance occur in a regular weekly cycle. Subjects were 13 color matchers and 30 printers who worked rotating shifts. Data were drawn from production records for 27 pairs of multicolor jobs performed over three four-week periods. The swallowtail hypothesis was upheld for three criteria: color matching time (R2 = .55), printing press time (R2 = .55), and printing paper conserved or wasted (R2 = .83). Job length (difficulty), time period (denoting organizational dynamics taking place), and whether the job pair occurred in the Monday-Wednesday, or Thursday-Saturday part of the week (semicycle) served as control variables.
This article concerns a cross-level formal identity between systems at the level of the organism and the level of an organization. It discusses catastrophe modeling for a class of theories, opponent process models, particularly two that have been proposed for drug addiction and the job satisfaction-performance relationship. The resulting models are then expanded to butterfly catastrophes; results converge with models proposed from other vantage points. While job satisfaction and drug addiction appear to have little to do with each other, the mathematical modeling common to them offers a systemic link between an individual and a foreign chemical substance, and an individual within a job in an organization.