Hi dear R users, 1) I would like to know if there is a simple way to define a vglm family which would be a mix of poisson variables and bernoulli variables (0/1 response) for idea this would be invoked like this: vglm(...,family=mixpoissonmultinom(npoisson,n01response)) where the n's give the number of each type of response. 2) and a simpler question : How to use constraints in rrvglm? for example, i want to regress X1 X2 X3 X4 (poisson variables with log-link) on two factor-type variables N1, N2 but i would like to use X1 and X2 [or something like 1(X1>X2)] in the estimation of X3 and X4 (but not in X1 X2 estimation of course). i can do it with simple vglm (with the constraints matrices) but with rr-vglm i can't. Excuse me if my questions are silly and for my bad english. Benoit J. R-fan PS: the final purpose would be to regress something like X1,X2,X3,X4 1(X1>X2) 1(X3>X4) on N1, N2 (for the part depending on X1,X2) and N1,N2,X1,X2 [or N1,N2,1(X1>X2) ] for the responses depending on X3,X4. X3,X4 could be interpreted like second period variables and X1,X2 like first period variables. -- View this message in context: http://www.nabble.com/R-vglm-new-family-writing%3A-mix-Poisson-multinomial-tp14660710p14660710.html Sent from the R help mailing list archive at Nabble.com.