Functions & Formulae

Maps the proportions of patients with a favourable outcome in the test and active control arms of a two-arm randomised trial, the arm sizes, a normal critical value and a margin fixed in the protocol to the two-sided interval for the risk difference and to the readings for non-inferiority and superiority. The steps before the decision are live records. The risk difference d is the test proportion minus the control proportion, the difference of HE-FM-ARR-001 with its sign reversed, because HE-FM-ARR-001 subtracts the intervention risk of an adverse event from the comparator risk and HE-AS-ARR-002 reverses the subtraction for a beneficial outcome. Each arm's standard error is HE-FM-BINOM-004, the variance of a difference of two independent arm estimates is the sum of their variances as in HE-VR-AN-002 and HE-FM-NMA-001, and the interval limits are the Wald limits of HE-FM-AN-001. HE-FM-ACTR-001 adds the comparison of the lower limit with minus the margin and with zero. The article's economic check is a citation of live records, the incremental net health benefit being HE-FM-CET-002, its break-even shortfall in cures being HE-FM-CET-002 solved for the shortfall under the article's illustrative linear cost and QALY model (compare the break-even price of HE-FM-BEA-001), and the probability of a positive net health benefit following the z statistic of HE-FM-AN-004. Bioequivalence on the ratio scale is HE-FM-ANDA-001, and the least-cost choice once outcomes are shown to be equivalent is HE-FM-CMA-001. Notation follows the Active Control Trial article.