How to trend the last two months (difference in percent)

[Badshaah]

If we have past all month file and , new file with current month then how we calculate the that current month from one file and last month from all month file
Percent difference

[Kurt_Bremser]

Please supply example data in a data step so we have something to play with.

[gamotte · Accepted solution]

Hi,

data old new;
    infile datalines dlm=",";
    format month x 2.;
    input month x;
    if month=4 then output new;
    else output old;
    datalines;
1,10,
2,5,
3,12,
4,15
;
run;

data want;
    set old new end=a;
    y=lag(x);

    if a then do;
        diff=100*(x-y)/y;
        output;
    end;

	drop y;
run;

[Badshaah]

Grand salute gamotte.