I'm using Movielens data set http://grouplens.org/datasets/movielens/ to do a class project. The data set contains rating data which has userid, movieid. I am able to output pairs for all the movies a user has rated. I repeat this for all users and now I get a set of such pairs. I have to compute lift between each pair of movies using map reduce paradigm. I'm running out of ideas on how to do this. Can someone please throw pointers ?