Commentary: statistical analysis of 2 × 2 tables in biomarker studies 2) study design and statistical tests.

In this article the importance of study design will be emphasized, statistical methods for analysing the data are described and some of the implications of these method are discussed. How these issues relate to the use of SpIN and SnOUT rules are reviewed.

Commentary: statistical analysis of 2 × 2 tables in biomarker studies 3) design, interpretation and guidelines.

This article discusses issues associated with the design and interpretation of biomarker studies, points to various guidelines and lists points to look out for in assessing studies.

Commentary: statistical analysis of 2 × 2 tables in biomarker studies 1) the four 'indices of test validity'.

Diagnostic statistics such as sensitivity and specificity are widely used in the assessment of biomarkers. Interpretation of these and other statistics derived from a 2 × 2 table can be complex. The properties of the commonly used statistics are discussed. The object is to provide help in their interpretation for authors designing studies and the subsequent reporting of results and to referees and others who assess such papers.