Related Experiment Video
Updated: May 5, 2026

Establishment of Rat Models Mimicking Gender-affirming Hormone Therapies
Published on: January 10, 2025
Testing for qualitative interaction using ratios of treatment differences
Andreas Kitsche1, Ludwig A Hothorn
1Institut für Biostatistik, Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany.
Abstract:
Testing for or against a qualitative interaction is relevant in randomized clinical trials that use a common primary factor treatment and have a secondary factor, such as the centre, region, subgroup, gender or biomarker. Interaction contrasts are formulated for ratios of differences between the levels of the primary treatment factor. Simultaneous confidence intervals allow for interpreting the magnitude and the relevance of the qualitative interaction. The proposed method is demonstrated by means of a multi-centre clinical trial, using the R package mratios.
Related Concept Videos
Sign Test for Matched Pairs
To conduct the sign test, we first calculate the differences in...
Cochran's Q Test
Test for Homogeneity
Behrens–Fisher Test
This test...
Comparing Experimental Results: Student's t-Test
Significance Testing: Overview

