topic Re: assign unscheduled visits in SAS Programming

assign unscheduled visits

thanikondharish — Sat, 18 Aug 2018 10:37:07 GMT

data s ;
input subjid $ visit $ visit_num date:ddmmyy. ;
format date date9. ;
cards ;
101 visit1 1 07-01-2018
101 visit2 2 18-01-2018
101 unc 1 09-01-2018
101 visit3 3 26-01-2018
101 unc 3 03-02-2018
102 visit1 1 07-01-2018
102 visit2 2 18-01-2018
102 unc 3 26-01-2018
102 unc 1 08-01-2018
102 unc 4 03-02-2018

;

in above data has some unscheduled visit how to fill up

like see below

subjid	visit	visit_num	date	new_visit
101	visit1	1	07JAN2018	1
101	unc	1	09JAN2018	1.1
101	visit2	2	18JAN2018	2
101	visit3	3	26JAN2018	3
101	unc	3	03FEB2018	3.1
102	visit1	1	07JAN2018	1
102	unc	1	08JAN2018	1.1
102	visit2	2	18JAN2018	2
102	unc	3	26JAN2018	2.1
102	unc	4	03FEB2018	2.2

Re: assign unscheduled visits

PaigeMiller — Sat, 18 Aug 2018 11:26:36 GMT

data want;
    set have;
    if visit^='unc' then new_visit=visit_num;
    else if visit='unc' then new_visit+0.1;
run;

You don't say what should happen in there are more than 9 "unc" per visit, this method would fail in that case.

Re: assign unscheduled visits

Ksharp — Sat, 18 Aug 2018 11:29:34 GMT

data s ;
input subjid $ visit $ visit_num date:ddmmyy. ;
format date date9. ;
cards ;
101 visit1 1 07-01-2018
101 visit2 2 18-01-2018
101 unc 1 09-01-2018
101 visit3 3 26-01-2018
101 unc 3 03-02-2018
102 visit1 1 07-01-2018
102 visit2 2 18-01-2018
102 unc 3 26-01-2018
102 unc 1 08-01-2018
102 unc 4 03-02-2018
;

proc sort data=s out=temp;
by subjid visit_num;
run;
data temp;
 set temp;
 by subjid;
 if first.subjid then group=0;
 if visit=: 'visit' then group+1;
run;
data want;
 set temp;
 by subjid group;
 if first.group then m=-1;
 m+1;
 if first.visit_num then new_visit=put(visit_num,best8. -l);
  else new_visit=catx('.',visit_num,m);
 drop m;
run;
data s ;
input subjid $ visit $ visit_num date:ddmmyy. ;
format date date9. ;
cards ;
101 visit1 1 07-01-2018
101 visit2 2 18-01-2018
101 unc 1 09-01-2018
101 visit3 3 26-01-2018
101 unc 3 03-02-2018
102 visit1 1 07-01-2018
102 visit2 2 18-01-2018
102 unc 3 26-01-2018
102 unc 1 08-01-2018
102 unc 4 03-02-2018
;

proc sort data=s out=temp;
by subjid visit_num;
run;
data temp;
 set temp;
 by subjid;
 if first.subjid then group=0;
 if visit=: 'visit' then group+1;
run;
data want;
 set temp;
 by subjid group;
 if first.group then m=-1;
 m+1;
 if first.group then new_visit=put(group,best8. -l);
  else new_visit=catx('.',group,m);
 drop m group;
run;

Re: assign unscheduled visits

Haikuo — Sat, 18 Aug 2018 15:31:26 GMT

data s;
	input subjid $ visit $ visit_num date:ddmmyy.;
	format date date9.;
	cards;
101 visit1 1 07-01-2018
101 visit2 2 18-01-2018
101 unc 1 09-01-2018
101 visit3 3 26-01-2018
101 unc 3 03-02-2018
102 visit1 1 07-01-2018
102 visit2 2 18-01-2018
102 unc 3 26-01-2018
102 unc 1 08-01-2018
102 unc 4 03-02-2018
;

proc sort data=s out=h1;
	by subjid date;
run;

data want;
	set h1;
	retain _base _unit;

	if visit=:'visit' then
		do;
			new_visit=visit_num;
			_base=visit_num;
			_unit=0;
		end;
	else
		do;
			_unit+0.1;
			new_visit=_base+_unit;
		end;

		drop _:;
run;

Re: assign unscheduled visits

FreelanceReinh — Sat, 18 Aug 2018 21:39:27 GMT

I'd like to point out that creating NEW_VISIT as a numeric variable involves the risk of numeric representation issues. (I worked on a clinical research project where exactly this had happened.)

Example (SAS log):

1    data bad;
2    new_visit=1.1;
3    new_visit+0.1;
4    if new_visit=1.2;
5    run;

NOTE: The data set WORK.BAD has 0 observations and 1 variables.

So, if it must be numeric (e.g. following CDISC recommendations on VISITNUM), precautions should be taken to ensure "clean" values, i.e. standard internal representations of 1.1, 1.2, etc. This can be achieved using the ROUND function, e.g.

new_visit=round(new_visit, 1e-8);

(or apply the ROUND function already when NEW_VISIT is assigned a calculated value).