**3. Methods**

A qualitative method through semi-structured interviews has been applied with the aim of delving deeper into the use of social media by communication professionals specializing in health. The choice is relevant as the main contribution of this qualitative study is to explore and understand some features of the communication of these colleges.

Qualitative research (QR) is useful for analyzing and understanding interpersonal relationships, behavioral experiences and variables such as opinions, perceptions, motivations and attitudes [67,68]. These variables are of interest in the field of communication. Moreover, the flexible and eminently inductive nature of QR is particularly suitable for seeking explanations for communication phenomena. Atlas.ti is the tool used to systemize the data and provide the desirable insights.

However, given the novelty of the issues being discussed and the need to ensure that the views of the most important actors were obtained, the flexibility of semi-structured interviews greatly outweighed the limitations on statistical analysis that would result [69–72]. In fact, flexibility both in designing and refining the interview guides and in actually conducting the interviews is probably the most important key to success in using this technique. This kind of interviewing also allowed the research to explore some of the underlying motives more directly [73]. Hence, semi-structured interviews using a deductive approach [74] were chosen in order to allow the participants a degree of freedom to explain their thoughts and to highlight areas of particular interest and expertise that they felt they had [75], as well as to enable certain responses to be questioned in greater depth, and in particular to bring out and resolve apparent contradictions.

The research team developed a protocol for semi-structured guides, that included five phases: (1) identifying the prerequisites for using semi-structured interviews; (2) retrieving and using previous knowledge; (3) formulating the preliminary semi-structured interview guide; (4) pilot testing the guide; and (5) presenting the complete semi-structured interview guide.

The interviews were carried out by the authors.

All 52 of the OMC in Spain were contacted, addressing the person in charge of communication or, whenever this information was not publicly available, addressing the Dean as the head representative. Of the OMCs, 38 showed interest in participation; they represented 73.07% of the total. The high participation of the OMC allowed to obtain information from a highly representative group. For this reason, it was considered interesting to include some statistical data, which are reflected in tables.

The guide included three predefined categories. At first in order to know the profile the professional who lead the communication in the o fficial medical colleges, they were asked some data about their functions and tasks, as well as the labor seniority, based on a validated tool by European Monitor Communication studies [76]. It was also considered important to know first of all aspects related to gender and age and especially those related to their work situation and whether there were communication cabinets in the OMC and whether the professionals responsible for them were experts with communication training.

The first category was regarding the involvement of the o fficial medical colleges' stakeholders. The role of health institutions, health professional, hospital groups, patients and family members or society were discussed. This debate helped us to have enough knowledge to map the stakeholders with whom they were dealing.

Second, we were interested in knowing the importance of communication professionals in the OMC and their use of social media for their work. The main reasons why they use social media in their professional routine (as a source of information, to interact with its stakeholders, as a communication channel, to establish professional relationships, to search for stories or to contrast information) were discussed in the interviews.

Finally, the third category was related OMC as producers of heath information. Social media has brought opportunities and challenges in health field, so we were interested about how social media contribute to the construction of agenda-setting in the health sector.
