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A statistical model is given for representing the several components of variability present in measurements (e.g., DMFS scores) given by examiners to patients. Methods for making inferences about the intraclass correlation coefficient of reliability are presented and illustrated on a real set of data. The proper analysis of data from a reliability study is shown to depend on the planned design and analysis of the clinical or field trial to be conducted following the reliability trial. [ABSTRACT FROM AUTHOR]

One hundred eighty-three Chinese students of grades five, eight, and 11 from urban schools and 153 students from rural schools took risk-taking and test-wiseness tests. The K-R 20 reliabilities of the risk measure ranged from .46 to .87 and were approximately the same magnitudes as those reported for comparable American samples. The grade by residence-areas interaction and the simple effects of grade were significant. The residence simple effects only related to risk taking for grade eight. Chinese and American students had the same mean risk score but with opposite direction. The K-R 20 values for the four TW subscales were low. An interaction was found for the grade by residence multivariate analysis of variance. Additional multivariate simple effect tests indicated there were relationships between grade and TW, and residence (grades eight and 11 only) and TW. Chinese students were consistently lower on mean TW than their American counterparts. [ABSTRACT FROM AUTHOR]

This article discusses research on dental caries and the effectiveness of preventive dentistry. The article reports on clinical studies conducted to examine the prevention of oral disease in terms of the availability of dental care and oral hygiene. This evaluation of preventive dentistry involved examining the prevalence of dental caries and their treatment in communities for adults and children. Information is also provided on hygiene education and products, as well as on behavior modification and the evaluation of the study.

Within- and between-examiner reliability estimates were considered for standardization data. However, within-examiner stability was demonstrated to be the important measure of examiner consistency in the clinical trial because it directly affects the precision of the study. Finally, an argument is also made against the use of reversal rates in the assessment of examiner consistency. [ABSTRACT FROM AUTHOR]

For an experimental study with pre- and post-DMFS measures two methods of analysis were compared with respect to precision. It is shown that for large sample size, the analysis of covariance with the post-DMFS measure as criterion and the pre-DMFS measure as the covariate will be more precise than the analysis of variance of increment scores as the value of β differs from 1. When β is approximately 1, the two techniques will have essentially the same precision. The dental researcher interested in precision is advised, therefore, to use analysis of covariance with the pre-DMFS measure as the covariate and the post-measure as criterion rather than the traditional analysis of variance of increment scores. For large sample size, the precision of the former will tend to be at least that of the latter. The researcher is not encouraged to use analysis of covariance with the increment as the criterion; if the procedure increases precision over analysis of variance of the increments, it merely indicates that analysis of covariance (with the post-measure as criterion) should have been used originally. [ABSTRACT FROM AUTHOR]