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.
Keywords: Integrated Management System (IMS); ISO 9001:2000; ISO 14001:2004; Management System (MS)