Centre for Evidence-Based Medicine
This short article gives a brief guide to the different study types and a comparison of the advantages and disadvantages of the different types of study.
The Number Needed to Treat (NNT) is the number of patients you need to treat to prevent one additional bad outcome (death, stroke, etc.).
To understand what is meant by the terms SpPin and SnNout, we need to understand the notions of sensitivity and specificity.
Pretest Probability is defined as the probability of a patient having the target disorder before a diagnostic test result is known.
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 expected in a patient without the target disorder.
This exercise is designed to walk you through the process of going from your “PICO” question to the steps of a rapid search for the evidence.
This document explains the background to the Oxford Centre for Evidence Based Medicine’s Levels of Evidence.
This must be read before using the Levels: no evidence ranking system or decision tool can be used without a healthy dose of judgment and thought.
This is the first version of the Levels of Evidence, last revised in March 2009