Precision of Qualitative Tests

In order to assess the precision of your qualitative diagnostic test, calculate measures of spread in your outcome data, e.g., SEs (standard errors) or 95 % confidence intervals (±2SEMS). The SEs of the sensitivity and specificity are calculated as follows.

Sensitivity (if sens = a/(a+c), then its SE = д/ ac/(a+c)3)

Specificity (if spec = d/(b + d)),......

As an alternative, the underneath procedure is adequate. If 95 % ci intervals cross a prior defined boundary, then the diagnostis test will not be valid (e.g., a boundary of 0.50 or 0.55 may be used). The STARD (standards for reporting diagnostic accuracy) Working Party (Sect. 10.7) says that precision of a qualitative diagnostic test is, traditionally, rarely assessed, and that, therefore, many tests, that are routinely used today, have been erroneously been validated in the past.

Statistics for Providing Quality Criteria for Diagnostic Tests, Validity, Reproducibility, and Precision of Quantitative Tests

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