  Product lines (PL) modeling have proven to be an effective approach to reuse
in software development.Several variability approaches were developed to plan
requirements reuse, but only little of them actuallyaddress the issue of
deriving product requirements.This paper presents a method, RED-PL that intends
to support requirements derivation. The originality ofthe proposed approach is
that (i) it is user-oriented, (ii) it guides product requirements elicitation
andderivation as a decision making activity, and (iii) it provides systematic
and interactive guidance assistinganalysts in taking decisions about
requirements. The RED-PL methodological process was validatedin an industrial
setting by considering the requirement engineering phase of a product line of
blood analyzers.
