dat <- data.frame(pref, Q5r0, Q5r1, Q5r2, Q5r3, Q5r4, Q5r5, Q5r6, Q5r7, Q5r8, Q5r9, Q5r10, Q5r11, Q5r12, Q5r13, Q5r14, Q5r15, Q5r16, Q5r17, Q5r18, Q5r19, Q5r20, Q5r21, Q5r22, Q5r23, Q5r24, Q5r25, Q5r26, Q5r27, Q5r29, Q5r28, Q5r30, Q5r31, Q5r32, Q5r33)

library(pls)
library(flipFormat)
library(flipTransformations)

dat <- AsNumeric(ProcessQVariables(dat), binary = FALSE, remove.first = FALSE)
pls.model <- plsr(pref ~ ., data = dat, validation = "CV")