Logistic regression: Part 1
Am J Orthod Dentofacial Orthop 2017;151:824-5
I n the article discussing the chi-square test,1 I used a clinical trial scenario with the objective of assessing the clinical alignment efficiency of 2 types of wires. These wires (A and B) were used for 6 months in 2 patient groups, and the outcome recorded was binary: reaching complete alignment (success) or not reaching complete alignment (failure). Table I shows the tabulation of alignment successes and failures for each wire after 6 months of treatment and the calculation of risks and odds of success, and risk and odds ratios of alignment success vs failure. The chi-square test showed no evidence of a difference in the success of alignment after 6 months between the 2 wire groups; the P value was 0.36.