Collapsing data - factor variables not allowed r (101)

[Ivan Petrov]

Hello Statalist,

Let me introduce myself - I'm a beginner in the Stata world and would kindly ask for some assistance regarding a question I have.

I'd like to collapse the variable ilos_sum by 4 other variables (periodid code16n ndf patienthash).

To that end my steps are as follows:

collapse (sum) ilos_sum by(periodid code16n ndf patienthash)

To which I get factor variables not allowed r (101)

I've attempted several other approaches, including:
egen long aggregated=group(periodid code16n ndf patienthash) //grouping
collapse (sum) ilos_sum by(aggregated) //final aggregation

Unfortunately I could not find the necessary information to the best of my abilities in the forum or other sources. Everywhere we had aggregation by one variable only.

Thank you!

[Carlo Lazzaro]

Ivan:
welcome to the list.
As far as I can get it, a comma is probably missing in your temptative code.
Try, instead:

collapse (sum) ilos_sum, by(periodid code16n ndf patienthash)

[Ivan Petrov]

Ivan:
welcome to the list.
As far as I can get it, a comma is probably missing in your temptative code.
Try, instead:

collapse (sum) ilos_sum, by(periodid code16n ndf patienthash)

Thank you very much, Carlo! Appreciate the help.