The regulation of nursing practice today.

The interface and complexity of licensure and scope of practice issues with professional standards of practice can be very confusing, particularly because the vary from state to state. This article provides an overview of the influences of regulatory boards, professional nursing organizations, and employers on the nursing practice. The roles of both regulatory boards and professional organizations are reviewed, including authority sources and mission differences. The employer's role is reviewed briefly, including attempts to "narrow" the licensed nurse's scope of practice.

Critical thinking and belief in the paranormal: a re-evaluation.

This paper evaluates the claim that believers in the paranormal exhibit poor critical thinking ability relative to disbelievers, as manifested in their inability to evaluate the competence of experimental abstracts. It is argued that such differences reported elsewhere (Alcock & Otis, 1980; Gray & Mill, 1990) may be accountable for in terms of the action of cognitive dissonance, or as due to experimental artifacts. A study was conducted which attempted to overcome earlier methodological shortcomings, and which assessed the cognitive dissonance account of differential performance. Altogether, 117 participants were characterized as believers, neutrals or disbelievers according to a pre-measure. Subsequently, each participant was asked to evaluate an abbreviated experimental report which was either sympathetic or unsympathetic to parapsychology. No differences in assessment ratings were found, failing to replicate the claimed effect and supporting an account in terms of artifact. There was a significant tendency for those participants who received a paper which was incongruent with their a priori beliefs to rate it as less competently conducted and analysed than those who rated the congruent paper, in keeping with the cognitive dissonance account.

Statistical comparison of two ROC-curve estimates obtained from partially-paired datasets.

The authors propose a new generalized method for ROC-curve fitting and statistical testing that allows researchers to utilize all of the data collected in an experimental comparison of two diagnostic modalities, even if some patients have not been studied with both modalities. Their new algorithm, ROCKIT, subsumes previous algorithms as special cases. It conducts all analyses available from previous ROC software and provides 95% confidence intervals for all estimates. ROCKIT was tested on more than half a million computer-simulated datasets of various sizes and configurations representing a range of population ROC curves. The algorithm successfully converged for more than 99.8% of all datasets studied. The type I error rates of the new algorithm's statistical test for differences in Az estimates were excellent for datasets typically encountered in practice, but diverged from alpha for datasets arising from some extreme situations.

Variance-component modeling in the analysis of receiver operating characteristic index estimates.

RATIONALE AND OBJECTIVES: The authors performed this study to clarify and systematize the large number of variances and correlations observable with variance-component models of receiver operating characteristic (ROC) index estimates. MATERIALS AND METHODS: The authors present a variance-component model for ROC index estimates (and for differences between estimates) and show correspondences between the method of experimental replication and the random components in the model. The authors introduce a notation that identifies both the method of replication and, when examining estimate differences, the estimate pairing scheme. RESULTS: For models with three factors (modality, reader, case sample), the authors delineated four methods of replication and eight pairing schemes for generating estimate differences. For each of the resulting 32 replication-pairing combinations, the authors gave expressions for the variance of the difference and for the correlation between the two ROC index estimates. CONCLUSION: The variance-component approach is a useful statistical tool for modeling different sources of variation that contribute to the overall variance of ROC data and index estimates derived from those data.

Dorfman-Berbaum-Metz method for statistical analysis of multireader, multimodality receiver operating characteristic data: validation with computer simulation.

RATIONALE AND OBJECTIVES: The authors examined the relationship between the critical P value (alpha) and the empirical type I error rate when using the Dorfman-Berbaum-Metz (DMB) method for analysis of variance in multireader, multimodality receiver operating characteristic (ROC) data. METHODS: The authors developed a linear mixed-effect model to generate continuous, normally distributed random decision variables containing multiple sources (components) of variation. A range of magnitudes for these variance components was used to stimulate experiments in which multiple readers (three or five) read imaged obtained with two modalities from the same set of cases with no re-reading. Three binormal population ROC curves, with areas of 0.962, 0.855, and 0.702, were included. Case-sample sizes ranged from 50 to 400, and either 50% or 10% of cases were actually positive. For each experiment, 2,000 data sets were analyzed by the computer program, and the proportion of 2,000 modality differences that was found to be statistically significant at an alpha level of .05 was tubulated. RESULTS: The test for modality difference performed well for the low and intermediate ROC curves, even with small case samples. For the high ROC curve, the small-sample results were conservative. No relationship between observed type I error rate and the magnitude of data correlation was evident. CONCLUSION: For typical ROC curves, the DBM method is robust in testing for modality effects in the null case, given a sufficient sample size. Instructions for obtaining a free copy of the software are given.

Portal film enhancement: technique and clinical utility.

We report on the results a 3-year project which had as its goal the development of methods to enhance radiation portal films to improve their readability. We had previously reported on a portal film enhancement technique, contrast limited adaptive histogram equalization, which could enhance low contrast detail, but degraded sharply contrasted edges. A new method, unsharp masking followed by contrast limited adaptive histogram equalization, now appears to overcome this problem. A clinical trial to test whether enhanced portal films could be read more accurately than standard ones was undertaken. The trial involved 12 readers from two institutions doing 276 readings. In this trial the enhanced films were judged to be of higher quality than the non-enhanced films (p < .001) and were read more accurately (p = .026). The usefulness and difficulties of routinely performing portal film enhancement in a busy radiation therapy department are discussed.