From the proposed conceptualization of the construct ¿integration of management systems¿ like a ¿semantic diffused universe¿, based on the multidisciplinary confluence in its field of study, this thesis deal with three key aspects in its theoretical framework: the scope of integrated management systems, the definitions of construct and the methodological approaches used for its consecution. Together with this, it is carried out a bibliographic meta-analysis about consequences as a result of an integration process. Based on this theoretical framework it was formulated three objectives: the first one is to know the characteristics of integrated systems (semantic consideration) including Quality, Environment and Occupational Health and Safety systems based on international standards (scope consideration), and the methodological aspects which determine its structure (methodological consideration). The second objective focus on the advantages, disadvantages and difficulties appeared after a process of integration of management systems; observing its level of appearance and identifying the contingent aspects which influence in his performance. Finally, we analyze the impact of the integration process on one technical function involved, Occupational Health and Safety, evaluating how is the impact on their performance results, as well as on the management mechanisms that it uses. The research methodology used to contrast the hypotheses derived from these objectives is basically exploratory, with application of quantitative techniques: for the first objective we have used the ¿principal component analysis¿ multivariate technique, complemented with descriptive statistics. For the other two objectives were combined techniques of statistical inference and descriptive statistics. The results have shown the appearance of three levels of integration between the organizations in the sample, which can be characterized by two variables: the integration of the documentary structure of the new system and the level of integration of the map of processes. It has also verified that the integration of management systems provides multiple benefits to organizations, so generally is perceived as positive for them. There is also a positive relationship between level of integration and level of acquisition of such benefits. Finally, we have found that the occupational health and safety management system integration with other systems has a positive impact on the management and operation of the preventive processes and its performance. Likewise it can even be a contributing factor to the reduction of the accident rates of the company.

Els sistemes de gestió permeten millorar l'eficiència de les organitzacions i en aquest context, una organització pot tenir implantats múltiples sistemes. La forma preferible de gestionar-los és integrant-los, perquè s'aprofiten les sinèrgies existents entre sistemes. Existeixen molt pocs estudis empírics que analitzin la integració de sistemes. Així, l'objectiu d'aquesta tesi és conèixer i analitzar empíricament com integren les empreses els sistemes i com realitzen les auditories d'aquests.Les conclusions de l'anàlisi empírica realitzada són que les empreses:(1)integren majoritàriament els sistemes a un determinat nivell, i sembla que els models de gestió utilitzats i l'ordre d'implantació dels sistemes, condicionen aquest nivell,(2)duen a terme, majoritàriament, auditories del sistema integrades, essent el nivell d'integració de les internes superior al de les externes, i(3)en alguns aspectes, sembla que la integració de les auditories externes, està relacionada amb el nivell d'integració dels sistemes. / Management systems can improve the efficiency of organizations and in this context, an organization can have multiple systems in place. The preferable way to manage them is integrating them, so take advantage of synergies between existing systems.There are very few empirical studies that analyze systems integration. Hence, the objective of this thesis is to ascertain and analyze empirically how companies integrate systems and how perform their audits.(1)Conclusions of the empirical analysis carried out are that companies: mainly integrate systems at a certain level, and it appears that management models used and systems'implementation order, determine this level,(2)carried out, mostly, integrated system audits, being the level of integration of the internal higher than the external, and (3)in some respects, it seems that the integration of external audits is related to the level of systems integration.