During the last years there has been a growing interest in quality of prison life. Several researches have tried to measure the social climate of a prison through several methods. Quality of life has generally been associated with a good organization (material conditions, safety and services). In this sense, in England and Wales prisons are evaluated with Key Performance Indicators. Notwithstanding, in Spain, the Public Administration has not developed equivalent tools, although there is some research that has applied the Social Climate Scale by Moss or has tried to know the subjective perception of inmates' quality of life.

Therefore, the Research Group in Criminology and Criminal Justice System of Universitat Pompeu Fabra has translated -and used in three Catalan prisons- Cambridge Institute of Criminology's Measuring Quality of Prison Life (MQPL) survey. First analyses of the results show that prisons are differently evaluated depending on their management style. In this sense, the challenge is to discover which aspects are more relevant for inmates' quality of prison life.

In this context, our research is aimed to study the effect of cognitive-behavioral treatment programs in Catalan prisons for inmates' perception of the quality of prison life. More concretely, the objectives are:

a) To determine to which degree the treatment programs have an influence in quality of prison life.

b) To know if those programs have a different effect depending on the varying socio-demographical and penal characteristics of inmates.