Hi All,
Thank you for engaging in a new and interesting session today, featuring the Simulation App, created by Francois Rerolle.
As follow-up to some questions raised in class, we are posting a slightly modified HW assignment, that gives further details for q10-12. To (hopefully) make things simpler, we've specified which metrics to focus on for assessing interaction on the additive and multiplicative scales, and clarified that when we ask you to comment on interaction, we mean both scales. In class, Francois commented that he thought it is important to not only specify "multiplicative" but "multiplicative on the RR or OR scale". This is a fair point. To simplify things for the HW, we have specified that to assess additive interaction, please use either the Interaction Contrast of the Risk Difference or RERIrr; for multiplicative interaction, let's focus on the RR scale.
Lastly, a point was raised after class that in EPI203, there is a slide from your effect modification lecture set that mentions that when lines are parallel (with similar legend and set up as the app), this means that there is not interaction on the multiplicative scale. Please note, the Y axis in that slide is on the log scale, and is different from the Y axis scale on the app. So, this comment regarding parallel lines from epi 203 does not apply for assessing multiplicative interaction visually on the app.
Thank you and Good luck!
JMC