Identifying consecutive values

[ChiSAS25]

Can you help me program this algorithm that is giving me trouble?

I have a dataset (as the one I've attached) with patient ID and the difference in days between two dates, with a range of -21 to +7.

I need to identify patients who have two consecutive values of flag_KPI = 1 within the range [-21, 0).

If they have only one in the range [-21, 0), then I consider the case where they have two consecutive values of flag_KPI = 1, one in the window [-21, 0) and the other in the window [0, 7].

[LinusH]

Please attach data using a data step and datalines.
Also, try to visualize your requirement as an output data set.
What have yo tried so far?

[ChiSAS25]

Thnks for your reply

Hereafter:

data kpi_data;

    infile datalines dsd truncover;

    input SubjectId :8.

          differences_in_days :8.

          flag_KPI :8.;

datalines;

1,-21,1

1,-14,1

1,-7,1

2,-16,1

2,0,1

2,6,1

3,-16,

3,-9,1

3,5,

4,1,

5,-21,1

5,0,1

6,0,

7,-11,

7,1,

7,6,

8,-21,1

8,-11,1

8,0,1

9,-14,

9,-9,

9,-6,

9,1,

9,2,

10,-19,

10,-14,

10,-8,1

10,-5,

10,0,

11,-10,

11,-3,1

11,0,1

11,7,

12,-21,1

12,-4,1

12,1,1

12,2,1

12,2,1

12,7,

13,-15,1

13,2,

14,-15,1

14,-8,

14,3,1

15,-8,

15,1,1

16,-18,1

16,-15,1

16,-11,

16,-8,1

16,-4,

16,-3,

16,-2,

16,-1,1

16,5,1

16,6,1

17,-20,1

17,-14,1

17,-7,1

17,0,1

17,7,1

18,-21,1

18,-20,1

18,-13,1

18,-4,1

18,0,1

18,4,1

18,7,1

13,-17,1

13,-1,1

14,-15,1

14,-8,1

14,0,1

14,7,1

15,-21,1

15,-13,1

15,0,1

16,-21,1

16,-14,1

16,-7,1

16,0,1

16,1,1

17,-16,

17,-9,

17,-2,

17,0,

17,3,

17,4,

18,-17,1

18,-5,1

18,-2,

18,2,

18,5,

19,-15,

19,-1,1

20,-6,

20,-2,

20,6,

21,-21,

21,-20,

21,-18,1

21,-7,1

22,-20,1

22,-15,1

22,-6,1

22,4,

23,-18,

23,-14,

23,-11,

23,1,1

24,-14,1

24,-10,1

24,5,1

25,-1,1

25,-18,

25,-3,

26,-15,

26,0,1

27,-3,1

27,-4,1

28,-14,1

28,3,1

29,-10,1

29,6,1

30,-14,1

30,-11,

30,-8,

30,-1,1

30,3,1

;

run;

I tried using retain by creating two counters (one for days < 0 and one for days ≥ 0), but I wasn’t successful.

Thanks for any help