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Likelihood Ratios
Definition The Likelihood Ratio (LR) is the likelihood that a given test result would be expected in a patient with the target disorder compared to the likelihood that that same result would be...
View ArticlePretest Probability
Definition Pretest Probability is defined as the probability of a patient having the target disorder before a diagnostic test result is known. It represents the probability that a specific patient, say...
View ArticleSpPin and SnNout
To understand what is meant by the terms SpPin and SnNout, we need to understand the notions of sensitivity and specificity. SpPin When a sign, test or symptom has an extremely high specificity (say,...
View ArticleNumber Needed to Treat (NNT)
Definition – The Number Needed to Treat (NNT) is the number of patients you need to treat to prevent one additional bad outcome (death, stroke, etc.). For example, if a drug has an NNT of 5, it means...
View ArticleCATMaker and EBM Calculators
On this page you can download CATmaker, the CEBM’s venerable computer-assisted critical appraisal software, and use our interactive EBM calculators. Please note that you will need the Shockwave plug-in...
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Critical Appraisal tools
Critical appraisal is the systematic evaluation of clinical research papers in order to establish: Does this study address a clearly focused question? Did the study use valid methods to address this...
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