Creating a new unique ID variable from two variables in merged data with repetition of one variable

[gonzy31]

Hi all,

Would love some help with this, as I think I am doing something wrong here in SAS.  I merged multiple years of data, but I wanted to create a unique ID variable ("ID") to identify each unique physician ("phycode").  For each individual year, the "phycode" is unique for every physician.  However, the "phycode" is repeated in subsequent years for other physicians so both "phycode" and "year" are necessary to create a new unique ID in the dataset.

Here is what my data looks like now:

Phycode        Year

1                     2004

1                     2005

2                     2004

2                     2005

3                     2004

4                     2004

I want my output to produce a table like this in recognition that repeat phycodes in different years represent unique physicians (ID):

Phycode        Year              ID

1                     2004             1

1                     2005             2

2                     2004             3

2                     2005             4

3                     2004             5

4                     2004             6

Here is what I tried:

proc sort data=IN.NAMCS0514;

by phycode year;

run; 

data=UniqueID;

set NSS0514;

by phycode year;

if  first.phycode then ID=1;

ID +1;

run;

Thanks in advance for your help

[Astounding]

Well you could replace the last two statements with:

if first.year then ID + 1;

Alternatively, you don't really need an ID variable,  You could just use the combination of PHYCODE and YEAR to identify a physician.

[ChrisNZ]

Your output matches:

data UniqueID;

set NSS0514; 

ID +1;

run;

[gonzy31]

Thank you both! That worked perfectly.