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From P-Values to Objective Probabilities in Assessing Medical Treatments.

ABSTRACT: The assessment of the effectiveness of a treatment in a clinical trial, depends on calculating p-values. However, p-values are only indirect and partial indicators of a genuine effect. Particularly in situations where publication bias is very likely, assessment using a p-value of 0.05 may not be sufficiently cautious. In other situations it seems reasonable to believe that assessment based on p-values may be unduly conservative. Assessments could be improved by using prior information. This implies using a Bayesian approach to take account of prior probability. However, the use of prior information in the form of expert opinion can allow bias. A method is given here that applies to assessments already included or likely to be included in the Cochrane Collaboration, excluding those reviews concerning new drugs. This method uses prior information and a Bayesian approach, but the prior information comes not from expert opinion but simply from the distribution of effectiveness apparent in a random sample of summary statistics in the Cochrane Collaboration. The method takes certain types of summary statistics and their confidence intervals and with the help of a graph, translates this into probabilities that the treatments being trialled are effective.

SUBMITTER: Kault D

PROVIDER: S-EPMC4658034 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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From P-Values to Objective Probabilities in Assessing Medical Treatments.

Kault David D Kault Sam S

PloS one 20151124 11

The assessment of the effectiveness of a treatment in a clinical trial, depends on calculating p-values. However, p-values are only indirect and partial indicators of a genuine effect. Particularly in situations where publication bias is very likely, assessment using a p-value of 0.05 may not be sufficiently cautious. In other situations it seems reasonable to believe that assessment based on p-values may be unduly conservative. Assessments could be improved by using prior information. This impl ...[more]

PMID: 26600468

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Project description:BackgroundTeaching and assessment of communication skills have become essential in medical education. The Objective Structured Clinical Examination (OSCE) has been found as an appropriate means to assess communication skills within medical education. Studies have demonstrated the importance of a valid assessment of medical students' communication skills. Yet, the validity of the performance scores depends fundamentally on the quality of the rating scales used in an OSCE. Thus, this systematic review aimed at providing an overview of existing rating scales, describing their underlying definition of communication skills, determining the methodological quality of psychometric studies and the quality of psychometric properties of the identified rating scales.MethodsWe conducted a systematic review to identify psychometrically tested rating scales, which have been applied in OSCE settings to assess communication skills of medical students. Our search strategy comprised three databases (EMBASE, PsycINFO, and PubMed), reference tracking and consultation of experts. We included studies that reported psychometric properties of communication skills assessment rating scales used in OSCEs by examiners only. The methodological quality of included studies was assessed using the COnsensus based Standards for the selection of health status Measurement INstruments (COSMIN) checklist. The quality of psychometric properties was evaluated using the quality criteria of Terwee and colleagues.ResultsData of twelve studies reporting on eight rating scales on communication skills assessment in OSCEs were included. Five of eight rating scales were explicitly developed based on a specific definition of communication skills. The methodological quality of studies was mainly poor. The psychometric quality of the eight rating scales was mainly intermediate.DiscussionOur results reveal that future psychometric evaluation studies focusing on improving the methodological quality are needed in order to yield psychometrically sound results of the OSCEs assessing communication skills. This is especially important given that most OSCE rating scales are used for summative assessment, and thus have an impact on medical students' academic success.

Dataset Information

From P-Values to Objective Probabilities in Assessing Medical Treatments.

Publications

From P-Values to Objective Probabilities in Assessing Medical Treatments.

Similar Datasets

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