Date: Wed, 3 Apr 1996 09:25:57 EDT
Reply-To: whitloi1@WESTATPO.WESTAT.COM
Sender: "SAS(r) Discussion" <SAS-L@UGA.CC.UGA.EDU>
From: Ian Whitlock <whitloi1@WESTATPO.WESTAT.COM>
Subject: Re[2]: SASTip: Disassociating format from a variable
Subject: Re: SASTip: Disassociating format from a variable
Summary: An answer is given to the question - What should one do when
codes change meaning?
Respondent: Ian Whitlock <whitloi1@westat.com>
Mike Sommers <MSOMMERS@CI.MADISON.WI.US> posed a common and interesting
problem which I do not think has yet been adequately addressed. He has
a variable ACCDTYPE (accident type) with integer code values that
changed meaning in 1994. For example, the old code 8 for accidents
involving pedestrians was changed to 5. Although he doesn't explicitly
say it, there is probably a new 8 with a totally different meaning.
In general he wants to know how to produce reports with the appropriate
words instead of codes. The problem here is that ACCDTYPE is not
really a variable in the data base sense that one value has a given
meaning for the entire column. Given an 8 you do not know what type of
accident it refers to until you also know the year of the
accident since 8 has multiple meanings.
To solve the problem one must first obtain a variable with constant
meaning. Let's assume that all codes are one or two digits. Then
if year ( accddate ) <= 1993 then accdtype = 100 + accdtype ;
else
accdtype = 200 + accdtype ;
Now the old 8 is 108 and the new 8 is 208 and both 108 and 208 have a
constant meaning. Hence one can assign a format to the recoded ACCDTYPE
without any problem.
108 = "Pedestrian"
205 = "Pedestrian"
208 = "Other"
If one has the power, simply apply the sensible coding scheme given
above through out the system. If one does not have that kind of power,
but does have control of the data base, recode as given above on entry
into data base. In general programmers don't have this power, but they
can make it a view for reports.
data db.accdview / view = db.accdview ;
set db.------ ;
if year ( accddate ) <= 1993 then accdtype = 100 + accdtype ;
else
accdtype = 200 + accdtype ;
run ;
Now the report programs can refer to DB.ACCDVIEW without problem and
no space is wasted trying to maintain a corrected version of a database
over which you don't have control.
Ian Whitlock
