Hi, First of all, I apologize to up this post but it is probably the closest one that relates to my understanding issues. I feel like I am about to grasp all these concepts but there are still blurry parts concerning definitions. - What's the difference between the "true responders" and the "responders" you mentioned in the definitions? Or is it simply language abuse? - For the % Response, I don't understand what the "proportion of true responders" is. Is it the proportion of responders in each decile calculated with respect to the total number of responders (on the whole data set), or the proportion of responders in each decile with respect to the size of the decile (number of participants in each decile)? To clear things up, say the whole data set contains data about 20,000 individuals, among which 5,000 gave a positive response (say, a donation, associated with a primary event). With a certain predictive model, I get the "best 5%" of my population (which gives me in total 1,000 individuals, i.e. the ones most likely to donate provided that the predictive model is decent), "next best 5%", and so on, which gives me all my deciles. Now imagine that I have a great model and, among these 1,000 individuals, it appears that 760 of them donated. Then, what will my % Response be? Will it be 760/5000 (=15.2%) or rather 760/1000 (=76%)? My guess goes towards the first choice (15.2%), but the definition I gave might not correspond to % Response but rather to % Captured Response. - I don't understand SAS EM's notion of "cumulative". To me, cumulative should add up to 100%, however it is never the case here (except for Cumulative % Captured Response). Therefore, I don't understand the notion of Cumulative % Response. - I don't understand the notion of % Captured Response and of its Cumulative counterpart. What's the difference between % Response and % Captured Response? I think that, with these aspects cleared up, I'll get a better understanding of the notion of lift. Thanks in advance if anybody answers this message, Yann.
... View more