The calibration of a sit-ups task using the Rasch Poisson Counts model.

The purpose of this study was to calibrate a nationally used sit-ups test using the Rasch Poisson Counts model and evaluate the model-data fit. The total number of subjects was 8,723, consisting of 4,486 girls and 4,237 boys, ages 10 to 18. The estimated difficulty of the sit-ups task was -2.80, which was appropriate for a majority of examinees whose ability levels ranged from .09 to 1.39. After the calibration, boys and girls as well as different age groups were compared under the same metric. Graphs of the model-data fit demonstrated that the model-data fit at a low ability level was not as good as the fit at a high ability, which could be caused by violation of assumptions of the model that examinees have the same performance speed throughout the test and that the speed at a given time is independent of the number of sit-ups completed so far.

The difficulty of sit-ups tests: an empirical investigation.

This study estimated the difficulty of various sit-ups tests using an item response theory (IRT) model, the Rasch Poisson Counts model. Scores were obtained on 18 sit-ups tests. All tests were thought to vary in difficulty based on clinical observations. Item difficulty was defined by the Poisson model as the difficulty of Step 1, where the difficulty of a step represented the difficulty of completing a sit-up. The difficulty values of the tests ranged from -4.02 to -3.57. The easiest test was executed with hands on thighs and feet anchored. Most tests had good fit values. The results demonstrated that a variety of sit-ups tests can provide a range of difficulties and variety in forming a sit-ups test bank.

A comparison of two criterion-referenced standard setting procedures for sports skills testing.

The application of criterion-referenced (CR) standard setting procedures in physical education has been limited to the examinee-centered model known as criterion groups. Alternative examinee-centered approaches are available but have not been applied in sport skills testing. The purpose of this study was to compare two examinee-centered models for setting performance standards for a sport skills test battery. CR performance standards were determined for the tennis skills test battery published in Tennis skills test manual (Hensley, 1989) using the borderline group (BG) (Livingston & Zieky, 1982) and criterion groups (CG) (Berk, 1976) models. The comparison of these two methods demonstrated that the CG method consistently produced performance standards that were lower than the BG method. In one instance the BG method produced a standard that was clearly unreasonable. Estimates of CR reliability for the CG standards (.76 less than or equal to P less than or equal to .93; .52 less than or equal to Kq less than or equal to .86) were higher than BG estimates (.55 less than or equal to P less than or equal to .84; .11 less than or equal to Kq less than or equal to .68). Although each method has strengths, neither is without problems. Results from this study suggest these two methods might be combined to minimize the problems associated with each. This combined method should produce standards with improved accuracy, validity, and reliability.

Item response theory and the measurement of motor behavior.

Item response theory (IRT) has been the focus of intense research and development activity in educational and psychological measurement during the past decade. Because this theory can provide more precise information about test items than other theories usually used in measuring motor behavior, the application of IRT in physical education and exercise science merits investigation. In IRT, the difficulty level of each item (e.g., trial or task) can be estimated and placed on the same scale as the ability of the examinee. Using this information, the test developer can determine the ability levels at which the test functions best. Equating the scores of individuals on two or more items or tests can be handled efficiently by applying IRT. The precision of the identification of performance standards in a mastery test context can be enhanced, as can adaptive testing procedures. In this tutorial, several potential benefits of applying IRT to the measurement of motor behavior were described. An example is provided using bowling data and applying the graded-response form of the Rasch IRT model. The data were calibrated and the goodness of fit was examined. This analysis is described in a step-by-step approach. Limitations to using an IRT model with a test consisting of repeated measures were noted.

The validity generalization of distance run tests.

The validity generalization model was used to examine the generalizability of the validity of distance run tests as measures of cardiorespiratory function. A literature search was conducted to identify studies in which distance run test scores were correlated with VO2 max scores obtained from a stress test on a treadmill. The data base was limited to runs of at least one mile or 9 min and the VO2 max scores expressed as mL.kg-1.min-1. The concurrent validity of distance run tests was not shown to be generalizable across all situations. When the data were analyzed by gender, the validity of distance run tests was more generalizable for women than for men. In the analysis of test scores for boys and girls, the validities appeared to be generalizable, although the results should be interpreted with caution owing to small samples sizes.

Handedness and hand joint changes in rheumatoid arthritis.

This study investigates the relationship of hand use to the deforming hand joint changes of rheumatoid arthritis. Measurements of metacarpophalangeal lateral mobility, loss of metacarpophalangeal hyperextension, thumb metacarpophalangeal range of motion, and lateral pinch strength were statistically compared across dominant and nondominant hands of 51 adult subjects who had definite or classical rheumatoid arthritis. Incidence of boutonniere and swan neck deformities and distal radioulna laxity was also recorded. Results of a multivariate analysis of variance of the difference scores between dominant and nondominant measures were not significant. The authors concluded that the relationship of hand use to joint destruction is not yet clearly defined and further study is needed. Implications for treatment principles of joint protection are presented.

Methodological issues in short-term motor memory research.

Four methodological issues identified and studied by short-term motor memory researchers were examined in this paper: (a) the distributions of three commonly used measures of error (AE, CE, and VE); (b) statistical analysis of these scores as dependent measures in an experiment; (c) within-cell and experiment-wise estimates of the reliability of CE; and (d) the power of the statistical test with CE as the dependent measure. The first two sub-problems were explored theoretically, while the latter two were subjected to empirical examination using four data sets from previously published experiments. The distributions of AE and VE scores were described as non-normal under certain conditions, while the CE score distribution was shown to be normal. Therefore analyses of these three dependent measures may require different statistical procedures. In light of this information, the assumptions affecting estimates of reliability and power in an experimental framework were examined. Based on an analysis of the four data sets, a strategy was proposed in which a relatively small number of subjects could be utilized in an experiment without sacrificing desired experimental controls.

The participant-observer: a source of invalidity in measuring motor skills?

Test validity can be defined as the accuracy of a test score. Artifacts, sources of error that affect validity, have been studied in both research design and written test frameworks but have received little attention in the context of tests of motor behavior in an educational setting. One potential source of invalidity in motor skill testing is the presence of participant-observers. The participant-observer effect is defined as the influence of the presence of other subjects who are waiting to be tested or who have already been tested on subjects who are being tested. This study was designed to measure the test performances of 175 college women with participant-observers present and with participant-observers absent. The test was an overarm throw for speed measured by an incident light velocimeter. The data were analyzed using 2 X 4 fixed-effects analysis of variance. The presence of other participant-observers did not elicit performance scores that were different from those of subjects tested alone. Thus testing subjects in groups where one member of the group is tested while the others observe did not adversely affect performance on the overarm throw compared with that of subjects tested alone.

Measurement in occupational therapy.

Occupational therapists use many forms of measurement tools to assess the existing and potential functions of their clients. Too often the principles of measurement theory have not been applied in the development of such instruments and the resulting assessments have no established validity or reliability. This article presents basic measurement theory and appropriate procedures for estimating validity and reliability within an occupational therapy framework. Special considerations with regard to measurement of motor behavior are emphasized. An understanding of these assesment principles can enable a therapist to construct measurement scales that are valid, reliable, and yield data of scientific value.