ABSTRACT
Critical appraisal is a logical way of assessing the likely truth of a piece of research, evaluating the results in terms of individual patient care, and then assessing the whole and determining whether it is useful for one's practice. It combines some knowledge of trial design, a small amount of basic arithmetic and some qualitative judgements. The specificity of a test will depend upon the prevalence of other diseases in the population that might lead to false-positive results. An aspect to consider is whether the test is carried out the same way in the setting as it was in the study. Some diagnostic tests depend upon the skill of the person carrying out the test, and the skill of the people interpreting the test result. Tests may be carried out in different ways, and it is carried out the same way in the local hospital or laboratory as it was in the study which evaluated the test.
