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B G Dodd

Publications and source records attributed to B G Dodd.

8 recordsLinked to original sources
PubMed1999

A comparison of three polytomous item response theory models in the context of testlet scoring.

An alternative to dichotomous scoring of multiple items anchored to a common stem is scoring these items as a single polytomous item (testlet scoring). This study systematically compared the partial credit model (PCM), the generalized partial credit model (GPCM), and the graded response model (GRM) in the context of testlet scoring. Data sets included a sample from the fall 1994 administration of the SAT I (N = 2,548) and a simulated data set. Theta estimation, information, and model fit were analyzed. Correlations among theta estimates ranged from 0.9748 to 0.9921. The relationship among the information functions of the PCM, GPCM and the GRM reflected the discrimination parameter estimates for the latter two models. Suggestions are made with regard to model selection.

Aptitude Tests↗
PubMed1999

Parameter recovery for the rating scale model using PARSCALE.

The purpose of the present study was to investigate item and trait parameter recovery for Andrich's rating scale model using the PARSCALE computer program. The four factors upon which the simulated data matrices varied were (a) the distribution of the scale values for the items (skewed or uniform), (b) the number of category response options (4 or 5), (c) the distribution of known trait levels (normal or skewed), and (d) the sample size (60, 125, 250, 500, or 1,000). Each condition was replicated 10 times resulting in 400 data matrices. Accurate item and trait parameter estimates were obtained for all sample sizes examined. As expected, sample size seemed to have little influence on the recovery of trait parameters but did influence item parameter recovery. The distribution of known trait levels did not seriously impact the item parameter recovery. It was concluded that Andrich's rating scale model allows for the use of considerably smaller calibration samples than are typically recommended for other polytomous IRT models.

Attitude↗
PubMed1997

Parameter recovery for the partial credit model using MULTILOG.

This study investigated parameter recovery for the partial credit model using the MULTILOG computer program. Factors studied were the sample size and the number of item parameters, which were manipulated by systematically varying the number of steps per item and the number of items. The findings suggest that the ratio of sample size to number of item parameters being estimated as a "rule of thumb" can be a more complete guideline when the number of steps per item is taken into account. Accurate estimation of ability can be obtained across all conditions, even with sample sizes as small as 250. With regard to estimation of step values, however, more caution is warranted. Accurate estimation of the step values of items which have more categories requires larger sample sizes for a given number of total parameters to be estimated.

Humans↗
PubMed1991

Drug use and life satisfaction among college students.

Individuals use a variety of drugs for a host of reasons and college students are no exception. Reasons provided for specific types of "recreational" drug use have included, but have not been limited to, medicinal, social, mood enhancement, and experimentation. In an attempt to discern the relationship between drug use and life satisfaction among college students, a slightly modified version of the National Institute on Drug Abuse (NIDA) Monitoring the Future Survey was administered to 683 students attending a major research university located in the southwestern United States. Based on the obtained study results a life satisfaction composite variable was created via factor analysis. Additionally, a polynomial multiple regression analysis was conducted to discern the association between the derived life satisfaction composite variable and drug use indices.

Adaptation, Psychological↗
PubMed1989

Discerning the epidemiology of drug use among a sample of college students.

Although estimates concerning the prevalence of various forms of substance abuse vary considerably, it is critical to note that even the more conservative estimates indicate a major public health problem. Furthermore, increased drug experimentation has been frequently associated with the college experience. Utilizing a slightly modified version of the National Institute on Drug Abuse (NIDA) Monitoring the Future Survey, the present study examined the epidemiology of self-reported drug taking behaviors (e.g., alcohol, marijuana, tranquilizers, stimulants, psychedelics, etc.) among a sample (n = 683) of students attending a major public university. Data analyses focused on the specific settings and social groupings in which drug use occurred as well as on the frequency and type(s) of drug taking behaviors. Based on the results yielded from a disjoint cluster analysis, four distinct groups of drug users were identified. These four groups then served as categories of the dependent variable in a discriminant function analysis. A general linear models procedure was employed to identify the more efficacious discriminating (i.e., independent) variables.

Adult↗
PubMed1981

Predicting vocational aptitude of mentally retarded persons: a comparison of assessment systems.

The relationship between the AAMD Adaptive Behavior Scale (ABS), the Behavioral Characteristics Progression Scale, and the McCarron-Dial Work Evaluation System and the vocational competencies of mentally retarded clients, as typically assessed by the San Francisco Vocational Competency Scale, was examined. Results were discussed in terms of the general applicability of the McCarron-Dial Work Evaluation System in assessing vocational potential of retarded persons when compared to either the ABS or the Behavioral Characteristics Progression Scale.

Adult↗