Abstract and Introduction
20.1.1 Abstract and Introduction
The structured abstract should enable the reader to assess the study hypothesis and methods quickly and easily.2 The context for the study question and the hypothesis (objective) should be clearly stated (eg, “To determine whether enalapril reduces left ventricular mass …”), the study design and population and setting from which the sample was drawn described, and the main outcome measures explained. The results should include some explanation of effect size, if appropriate, with point estimates and confidence intervals used to describe the results. The conclusions should follow from the results without overinterpreting the data. Abstract format is too brief to permit detailed explanation of statistical analyses, but a basic description may be appropriate (eg, “The screening test was validated by means of a bootstrap procedure and performance tested with a receiver operating characteristic curve.”).
The introduction should include a concise review of the relevant literature to provide a context for the study question and a rationale for the choice of a particular method. The study hypothesis or purpose should be clearly stated in the last sentence(s) before the “Methods” section. Results or conclusions do not belong in the introduction.