fit0	<- glm(y ∼ x1 + x2 + x3, family=binomial, data=data0) #reprise the fit
p	<- predict(fit0, newdata=data1) #default type is the linear predictor
group	<- cut(p, c(-Inf, quantile(p,(1:9)/10), Inf))
fit1	<- glm(y ∼ offset(p), family=binomial, data=data1)
fit2	<- glm(y ∼ p, family=binomial, data=data1)
fit3	<- glm(y ∼ −1 + group + offset(p), family=binomial, data=data1)