PHRM3031 Lecture 3: L3 - Randomised Controlled Trials 1
Document Summary
Randomised trials are designed to provide a rigorous test of the primary endpoint; statistically significant results on other endpoints in the study are often less reliable. Confidence intervals are a measure of the precision of the statistical result (assuming statistical and methodological assumptions are met) Relative measures provides a ratio measure of the effect relative to control: doesn"t take into account baseline risk tends to be more stable across different populations. Absolute measures provides a difference measure of the effect relative to control: takes into account baseline risk differs considerably across different populations. Ic incidence of the endpoint in the control group (%) It incidence of the endpoint in the intervention group (%) Relative risk ratio (rr) it / ic. Absolute risk reduction (arr) ic - it. Number needed to treat (nnt) 100 / arr. Provide a measure of statistical precision the smaller the interval the more precise the estimate.
