Hi Delphine,
Try Wickelmeier routines for Elimination-by-Aspects available in Matlab, or R. Also read his paper about pair-comparisons:
A Matlab Function to Estimate Choice Model Parameters from Paired-comparison Data.
Florian Wickelmaier and Christian Schmid
Behavior Research Methods, Instruments, & Computers
2004(36) pp. 29-40.
Good luck,
Julian VillegasMe pregunto de un modo pensativo
Que significa ser Colombiano?
No se le respondi. Es un acto de fe
JLB.