Hi @jimbarbour That makes sense. I have tried putting that call (missing) code in different places where I thought it should start afresh but with no luck. I am of course doing something wrong. Could you advise on where you would put it, if what you want is described as the following: For each admission row in the original have dataset, there was a diagnosis code, and there are several admission rows for the same ID, where different diagnosis codes are registered. What I meant with loop is those admission and discharge dates which I end up collapsing (when a new min_admission_date and max_discharge_date are created). What I want is that when these admission rows are collapsed, all the diagnoses codes that were registered there appear as in_diag_code1... N (depending on how many). So if one ID has 4 rows which were collapsed and end up appearing as one row in my want dataset, then the 4 diagnosis codes should appear in 4 columns. Then the SAME ID would have another 3 rows which were also collapsed and appear as another row in my want dataset, then for that row I want the 3 diagnosis codes in 3 columns next to it (which are then not necessarily the same as the 4 rows above it). As such, the same ID ends up having several rows in the want dataset which resulted after being collapsed, and their diagnosis codes are specific to each row (so the diagnosis codes that were part of all admissions which resulted in the one collapsed row in the want dataset). I hope you can guide me, this is the final step I need for magic to finally happen 🙂 Janet
... View more