Hello,

I need to collapse my dataset for a forestplot which will illustrate heterogeneity in outcome according to center in a multiple center study: mean Q1 (p25) and Q3 (p75).

I have the outcome CPCbon90days, the unique identifier Numéropatient and center NumeroCentre

I try:

collapse (mean) CPCbon90days (p25) (p75) , by(NumeroCentre)

Without success.

----------------------- copy starting from the next line -----------------------
Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input byte NumeroCentre int Numéropatient float CPCbon90days
1  1 1
1  2 0
1  3 0
1  4 0
1  5 0
1  6 0
1  7 0
1  8 0
1  9 0
1 10 0
1 11 0
1 12 0
1 13 0
1 14 0
1 15 0
1 16 0
1 17 0
1 18 0
1 19 0
1 20 0
end
------------------ copy up to and including the previous line ------------------

Thanks.