Aggregate a variable across observations by group in cumulative fashion

[r4321]

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 

[LinusH]

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

[PaigeMiller]

---

@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?

[r4321]

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.

[PaigeMiller · Accepted solution]

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;

[r4321]

Thank you