Integration of different data collection techniques using the propensity score

The present analysis has been made possible by the survey on graduates' condition that is carried out every year by the Interuniversity Consortium ALMALAUREA. The huge number of post-reform graduates involved (about 140,000) in the survey conducted in 2008 has determined the necessity to make a radical revision of the survey methods, so that survey costs and time are reduced. This objective has been achieved through the introduction of two survey methods: CAWI (Computer-Assisted Web Interview) and CATI (Computer-Assisted Telephone Interview). However, it is possible that the survey methods used may have influenced the answer given by graduates. In other words, since the information have been collected through different survey tools (CAWI and CATI), they may have caused distortions that are not casual. The aim of the present analysis is to measure and to evaluate the effect of the undergone treatment on the answers given by graduates, using the propensity score approach . In fact, many telephone and web studies have proposed the use of this approach in postsurvey impact evaluation of different interview techniques. Particularly, propensity score has been used in postsurvey weighting procedures to dicrease biases. The methodology so developed will provide a very valuable instrument for evaluating the actual reach and significance of the results presented by ALMALAUREA in its annual reports.