How SAS assign rank while the number of obs less than number of groups?

Phil_NZ — Sat, 06 Mar 2021 10:04:25 GMT

Hi all SAS Users,

Today I try to use PROC rank in my project, due to the characteristic, I need to rank 100 groups per year per country. However, in this year in this country, there are only 13 observation, I am quite surprise that SAS can assign some numbers over there. Can I ask how SAS can assign these rank_ numbers?

The value of variable need to be ranked

amihud
0.0005088943
1.4387286E-6
5.767935E-6
5.3867482E-7
2.1144515E-6
4.2862647E-6
0.0001175097
8.5303028E-6
0.000117864
3.4827424E-6
0.0000313065
0.0000173605
8.5760194E-6

And the result is

How come SAS rank 92 or 42 while there are only 13 obs over there.

Warm regards,

P/S: I think it is quite a bit irrelevant but my code is as below

proc rank data=work.trim_price groups=100 out=temp;
		  by LOC year;
                   Comment LOC  is country;
		  var amihud;
		  ranks rank_;
run;

Re: How SAS assign rank while the number of obs less than number of groups?

FreelanceReinh — Sat, 06 Mar 2021 10:57:01 GMT

Hi @Phil_NZ,

Because of the GROUPS= option the values of variable RANK_ aren't really ranks, but group numbers defined by the formula

floor(rank*k/(n+1))

where rank is the rank that you would obtain without the GROUPS= option, k is the value specified in the GROUPS= option and (since you use the default TIES=MEAN) n is the number of observations with nonmissing values of your analysis variable AMIHUD (see documentation).

So, in your example the ranks r = 1, 2, ..., 12, 13 are transformed into floor(r*100/14) = 7, 14, ..., 85, 92.

topic Re: How SAS assign rank while the number of obs less than number of groups? in SAS Programming

How SAS assign rank while the number of obs less than number of groups?

Re: How SAS assign rank while the number of obs less than number of groups?