This project is aimed to developing a conceptual map and a knowledge-base of mental health indicators suitable for mental-health planning which permits inter-regional comparisons, follow-up and evaluation of the health systems that currently exist in Spain. For this a mixed qualitative method was followed using frame analysis and nominal groups.
Frame analysis is a broadly defined method of enumerating and defining ideas and themes within a larger topic that is particularly useful for formalising concepts . Of the four components of frame analysis, we focused on "frame bridging," which manifested as collaborating with experts who are interested in topic but do not commonly interact due to different training backgrounds or other reasons, and on "frame amplification," or the clarifying and elaborating of a framework from which to think about the issue of discussion . Frame analysis has previously been applied to a wide range of social and health-related topics, such as consensus-building in online special-interest advocacy groups and understanding of the culture of nurse mangers . Two members of the core group with a background in mental health system research (LS-C), and mental health geography and data management (JAS), searched the relevant literature in PubMed and Google Scholar using the key words: 1) "Mental Health", 2) "Care", "System", "Policy", "Planning" and 3) "Indicator(s)"; as well as a review of other technical documents available such as lists of general indicators of health relevant to mental health, and mental health lists from international, European and national organisations. Also considered were various plans and health reports from the Autonomous Communities or regions in Spain and lists developed by scientific associations. As the aim of this project was to develop a taxonomy usable in Spain within the European context, indicator lists from the US were not included in the analysis. The two researchers arranged this content according to key topics and prepared a framing document and a list of key areas and questions to be debated by the nominal groups.
The nominal group technique helps to deal with ill-structured domains while it allows a more structured approach than focus groups, as well as the use of prior information and knowledge. Once ideas and related questions are listed, its relevance to the central problem can be discussed following a question made by the facilitator, ideas can be re-formulated and clustered into coherent groups. All members are encouraged to participate in the discussion following a sequential order and every round is followed by a final debate [14, 15]. In the health sector nominal groups have been previously used to develop the preliminary taxonomy of health related habits and lifestyle  and its integration into primary care .
An iterative process was followed to develop the preliminary taxonomy and the related knowledge-base. In all 14 experts in mental health service research and indicator analysis with very different background participated in two nominal groups: a core working group and an external group. The core working group was comprised of seven members: four psychiatrists with experience in the evaluation and management of services, one expert in data-analysis (Knowledge Discovery from Data -KDD) , a health geographer, and an expert in health and social management in the field of mental health. The core group hold three face-to-face meetings in 2009 and 2010, combined with three conference calls and periodic contact by e-mail.
Additionally, a panel of experts from the Scientific Association PSICOST provided external support to this core group. This external panel had seven members, a coordinator (LS) and a moderator (JAS). The panel also followed a nominal group methodology and it was comprised of two psychiatrists (LS and JCG), one psychologist (CR) with experience in services evaluation, a public health expert in epidemiology (JA), an expert in health-indicator data analysis (CG), and a public administration manager with experience in mental health and disability (FA).
For the development of this taxonomy the model and terminology used at the International Classification of Functioning (ICF)  was adopted for defining health constructs, domains and dimensions. For the definition of entities, their hierarchy and type, we used a basic formal terminology: <it is a>, <it is comprised of>, <it is part of>. A conceptual map was drafted using a tree structure for coding and organising the indicators. This approach had been used previously for the description of resource indicators and the use of mental health services in Spain and in other European countries . This diagram allows the organisation of indicators into classes (domains), subclasses (subdomains) and additional types. This structure allows the addition of new indicators or the subdivision of previously defined indicators where necessary, without altering the hierarchical structure of the taxonomic system.
Subsequently, the two reviewers developed a list of relevant databases, a wide-ranging list of mental health indicators, and a glossary. With respect to the database, and bearing in mind all the information available, the following question was formulated for the nominal expert panel: "Is this a relevant indicator for the evaluation of the mental health system in the various Autonomous Communities?". 'Relevant' was defined here as 'closely connected with the subject and valuable and useful to mental health planners and stakeholders' based on the definition provided by the Oxford Advanced Learner's Dictionary http://www.oxfordadvancedlearnersdictionary.com. The responses were organised into a 4-level Likert scale according to their relevance (none, doubtful, moderate and high).
The results were reviewed by the members of the working group and the information gathered was used to develop a definitive list which was added to the preliminary knowledge base and which can be seen at the Spanish Society of Psychiatry website SEP . The external nominal panel provided an evaluation of the relevance of the various indicators which was reviewed by the core working group.