23. Index test and reference standard results
What to write
Cross tabulation of the index test results (or their distribution) by the results of the reference standard.
Explanation
Research findings should be reproducible and verifiable by other scientists; this applies both to the testing procedures, to the conduct of the study and to the statistical analyses.
A cross tabulation of index test results against reference standard results facilitates recalculating measures of diagnostic accuracy. It also facilitates recalculating the proportion of study group participants with the target condition, which is useful as the sensitivity and specificity of a test may vary with disease prevalence.1,2 It also allows for performing alternative or additional analyses, such as meta-analysis.
Preferably, such tables should include actual numbers, not just percentages, because mistakes made by study authors in calculating estimates for sensitivity and specificity are not rare.
In the example, the authors provided a contingency table from which the number of true positives, false positives, false negatives and true negatives can be easily identified (Table 1).
Example
‘Table X shows pain over speed bumps in relation to diagnosis of appendicitis’.3 (See Table 1.)
Table 1: Example of contingency table from a study evaluating the accuracy of pain over speed bumps for diagnosis of appendicitis (adapted from Ashdown et al,3 with permission)
Appendicitis Pain over speed bumps Positive Negative Total Positive 33 21 54 Negative 1 9 10 Total 34 30 64
Training
The UK EQUATOR Centre runs training on how to write using reporting guidelines.
Discuss this item
Visit this items’ discussion page to ask questions and give feedback.
