Date:         Sat, 11 Dec 2004 14:50:04 -0700
Reply-To:     Jack Hamilton <JackHamilton@FIRSTHEALTH.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Jack Hamilton <JackHamilton@FIRSTHEALTH.COM>
Subject:      Re: newbie - avg time / avg charge betwn visits???
Comments: To: haleyjo@GMAIL.COM
Content-Type: text/plain; charset=us-ascii

Use the DATEPART function to get the date part of a SAS datetime value.
Use the LAG function to get the difference in value between two data
step iterations (an oversimplification of what LAG does, but it suffices
for this usage).

Here's a sample program:

=====
data visits;
   infile cards firstobs=2;
   input @1  member_no $4.
         @15 visit_dt  datetime.
         @43 visit_chg 5.;
   visit_da = datepart(visit_dt);
   format visit_da date9.  visit_chg 5.2;
   drop visit_dt;
cards;
Member_no    Visit_dt                     Visit_Chg
0001          22MAR2002:00:00:00          20.00
0001          22MAY2002:00:00:00           2.00
0001          22JUL2003:00:00:00          70.00
0001          22AUG2003:00:00:00           2.00
0001          22JAN2004:00:00:00          70.00
0002          29JUN2002:00:00:00           1.00
0002          15DEC2003:00:00:00           4.00
0003          22MAR2001:00:00:00          20.00
0003          22MAY2002:00:00:00           2.00
0003          22JUN2003:00:00:00          70.00
0003          29JUL2003:00:00:00           1.00
0003          15DEC2003:00:00:00           4.00
;;;;

proc sort data=visits;
   by member_no visit_da;
run;

data visit_sum;
   set visits;
   by member_no;
   prev_da = lag(visit_da);
   prev_chg = lag(visit_chg);
   format prev_da date9.  prev_chg 5.2;
   if first.member_no then
      do;
      visit_no = 0;
      prev_da = .;
      prev_chg = .;
      end;
   visit_no + 1;
   day_diff = visit_da - prev_da;
   chg_diff = visit_chg - prev_chg;
   format day_diff 4.0 chg_diff 6.2;
   put (_all_) (=);
run;

proc summary data=visit_sum nway missing;
   class visit_no;
   var day_diff chg_diff;
   output out=diffs (drop=_type_ _freq_)
          mean=;
run;

options nocenter;

title 'Proc SUMMARY Results';

proc print data=diffs;
run;

title 'Proc REPORT Results';

proc report data=visit_sum nowindows;
   column visit_no day_diff chg_diff;
   define visit_no / group;
   define day_diff / mean width=8;
   define chg_diff / mean width=8;
run;
=====

It produces this output:

=====
Proc SUMMARY Results

Obs    visit_no    day_diff    chg_diff

 1         1            .          .
 2         2          340       -11.00
 3         3          411        68.00
 4         4           34       -68.50
 5         5          146        35.50

Proc REPORT Results

   visit_no  day_diff  chg_diff
          1         .       .
          2       340    -11.00
          3       411     68.00
          4        34    -68.50
          5       146     35.50
=====

Note that I produced the final result in two ways: one using PROC
SUMMARY and PROC PRINT, the only using PROC REPORT.  You'd want to pick
one method.

The program could use some fine tuning; for example, since you know
that some calculations will produce missing values, you might want to
use an IF to suppress those calculations and the associated error
messages.  If wanted to get fancy, you could do all of the calcuations
in a single data step instead of a data step plus a proc.  You might
even be able to do everything in a single PROC REPORT with no data step
- would someone like to step up to the challenge?






--
JackHamilton@FirstHealth.com
Manager, Technical Development
Metrics Department, First Health
West Sacramento, California USA

Coelum, non animum mutant, qui trans mare currunt.


>>> "haleyjo" <haleyjo@GMAIL.COM> 12/11/2004 12:20 PM >>>
I have data similar to the following for our medical office:

Member_no    Visit_dt                     Visit_Chg
0001          22MAR2002:00:00:00          20.00
0001          22MAY2002:00:00:00           2.00
0001          22JUL2003:00:00:00          70.00
0001          22AUG2003:00:00:00           2.00
0001          22JAN2004:00:00:00          70.00
0002          29JUN2002:00:00:00           1.00
0002          15DEC2003:00:00:00           4.00
0003          22MAR2001:00:00:00          20.00
0003          22MAY2002:00:00:00           2.00
0003          22JUN2003:00:00:00          70.00
0003          29JUL2003:00:00:00           1.00
0003          15DEC2003:00:00:00           4.00

I want to find avg time between visits and avg cost between visits.
In
other words, avg time between 1st visit and second visit (overall),
avg
time between 2nd and 3rd, 3rd and 4th, 4th and 5th visits, etc.  Then,
similarly, avg charge between 1st visit and second visit (overall),
etc.

I have been reading about first. and last. - but not sure how to get
the 2nd, 3rd and 4th.  Just not sure where to begin.  I need to make
each visit a varible, right? Would proc transpose help me?  I also
need
to get rid of the hrs, min, sec on the dates.
someone point me in the right direction? thankyou. haleyjo


"MMS <firsthealth.com>" made the following annotations.
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