Dear R-help mailing list, I have the following types of data long form a<- ID Y 1 3 1 4 1 5 2 3 2 1 2 4 the broad form data is e<- e0 e1 e2 e3 3 1 3 4 3 2 3 4 I want to combine them as follows (neglecting totally e0) k<- ID Y Y+e 1 3 Y11 +e11= 3+1 1 4 Y12 + e12 = 4+3 1 5 Y13 + e13= 5+4 2 3 Y21 + e21 = 3+2 2 1 Y22 + e22 = 1+3 2 4 Y23 + e23 = 4+4 Thanks regards Emmanuel [[alternative HTML version deleted]]