This paper presents a framework based on a user driven methodology to obtain analytical models of MPI applications on parallel systems in a systematic and easy to use way. This methodology consists of two stages. In the first one, instrumentation of the source code is performed using CALL, which is a profiling tool for interacting with the code in an easy, simple and direct way. New features are added to CALL to obtain different performace metrics and store the performance information in XML files. Using this information, an analytical model of the performance behavior is obtained in the second stage by means of R, a language and environment for statistical analysis. The structure of the whole framework is detailed in this paper, and some selected examples are used to show its practical use.