Hello!   I am a fairly new SAS user, so forgive me if the solution is easy. I am using SAS 9.4.   I have a dataset which contains longitudinal data over several years, with multiple observations for each ID. I've coded in what quarter of the year the observation took place. It looks like this:   ID Date Variable Quarter A  xxxx  103        1 A  xxxx  91          1 A  xxxx  90          3 B  xxxx 98           1 B  xxxx  97          2 B  xxxx  80          2 B  xxxx  75          3 B  xxxx  70          4   The goal is to take the highest value of each quarter per subject and calculate their average. Thus, for B it would be [(98+97+75+70)/4)] - the 80 in quarter two should not be calculated). As you can see for A, the preferred value would be [(103+90)/2].   What I had thought was to create a multitude of datasets bringing in the highest value for each quarter, then merge them together to do the calculation, but I am sure there is an easier way to do it. How would you do this?   Thank you in advance! ... View more