| Purpose: The aim of this research is to study the degrees of integration of different Management systems (MS) within organizations.
Methodology: A questionnaire was mailed to 362 Spanish organizations asking about the level of integration of resources, documentation and procedures. All companies of the sample have, at least, ISO 9001:2000 and ISO 14001:2004 implemented. Multivariate statistical analysis was used to test the hypothesis: first reduction of data and then a cluster analysis in order to classify the organizations of the sample into few groups representing the levels of integration.
Findings: Companies are classified into three groups, each of them integrating at different levels: harmonization, cooperation and amalgamation. In harmonization (8 organizations) the level of integration is partial and cooperation (41 companies) is the next step, that is, more than partial integration but not full integration yet. Finally, the last group of companies (310 organizations) has full integration of their management systems. A great number of companies integrate their MS but there is a lack in understanding the concept of integration.
Research limitation: The sample is made up by Spanish companies. The regions participating in the study have an intensive level of certification, but the results cannot be applied to the rest of Europe before knowing other countries behavior in practice.
Practical implications: This study contributes in knowing what levels of integration companies can have. It can be useful in the creation of an internationally recognized guideline for integration.
Originality: This study is one of the first empirical researches about integration degrees. | 
Ph.D., Lic. Theses
