topic Aggregate a variable across observations by group in cumulative fashion in SAS Data Management

Aggregate a variable across observations by group in cumulative fashion

r4321 — Wed, 22 Nov 2017 21:40:01 GMT

Hello all,

I'm looking for code so that I can aggregate a variable across observations by group in a cumulative fashion... See below for desired result:

Unitid TimePeriod Variable DesiredVariable

1 1 1 1

1 2 0 1

1 3 0 1

1 4 2 3

1 5 0 3

2 1 0 0

2 2 4 4

2 3 0 4

2 4 1 5

2 5 1 6

If someone could help me out, then you guidance would be greatly appreciated!

Thank you,

Rich

Re: Aggregate a variable across observations by group in cumulative fashion

LinusH — Fri, 24 Nov 2017 16:33:45 GMT

Accumulating data should only be done for reporting purposes. How will the users consume this data?

Re: Aggregate a variable across observations by group in cumulative fashion

PaigeMiller — Fri, 24 Nov 2017 16:43:17 GMT

Assuming the data is sorted by UnitId and TimePeriod

UNTESTED CODE

data want;
    set have;
    by unitid;
    if first.unitid then sum=0;
    sum+variable;
run;

Re: Aggregate a variable across observations by group in cumulative fashion

PaigeMiller — Fri, 24 Nov 2017 23:15:28 GMT

@LinusH wrote:
Accumulating data should only be done for reporting purposes.

I have never heard such a rule. And furthermore, it doesn't seem like a rule I would follow anyway. Could you please explain?

Re: Aggregate a variable across observations by group in cumulative fashion

r4321 — Fri, 15 Dec 2017 15:28:00 GMT

Yeah, I don't believe such a rule exists either. But to let you in on my intent, it's to model the incrementally increasing threat posed by a particular effect across time. Thanks.

Re: Aggregate a variable across observations by group in cumulative fashion

r4321 — Fri, 15 Dec 2017 15:28:12 GMT

Thank you