Time period in Excel 2010 -

a simple question, quick googling did not prove fruitful.

basically, have column called "uniqueid", unique identifier people in dataset. uniqueids have multiple records, because there 1 record per year person stayed @ university. i'd create "time period" variable, first year, t= 1, second year t=2, third year t=3 etc. each unique id.

the following faster if spreadsheet sorted unique id;

=if(a2=a1,b1+1,1)

(assumes above formula in column b , data begins on row 2)

and, of course, copied down rows described above.

you find in spreadsheet containing many rows countif slow since looking through ever-increasing range sizes.