**5. Research methodologies for studying the HIV pandemic**

The sociological theories described in the previous section allow for investigating the phe‐ nomenon of HIV from its essential premise: HIV is a complex and dynamic social phenomenon that acquires different meanings depending on the social and cultural context of each society. These meanings, representations, perceptions, beliefs, values and life experiences will give meaning to and guide the behaviour and actions of people in relation to HIV. Furthermore, these different values and meanings influence the preventive practices that people adopt against HIV. Therefore, it is evidenced that there are qualitative aspects to the HIV phenom‐ enon that also need to be known in order to prevent and eradicate the pandemic [10]. For this reason, most of the interventions being carried out in this field take the social dimension of HIV into consideration.

Therefore, sociological theories described in the previous section allow for grasping the qualitative aspects of HIV. However, the study of HIV using these sociological theories can only be developed from qualitative research strategies. In the scientific arena, the discipline that has traditionally investigated HIV has, however, been clinical epidemiology. For this reason, the research found in scientific literature is mostly prevalence and/or ecological studies. Consequently, in overall terms, there is a predominance of knowledge based on data that mainly describes how the epidemic is distributed among the population, depending on certain factors [10]. Furthermore, the qualitative factors that define the phenomenon of the HIV epidemic have evidenced the need for developing research methodologies that enable the study of the epidemic, transcending the simple observation of how it is quantitatively distributed within a certain population [10].

Using a qualitative methodology allows us to understand and comprehend the phenomenol‐ ogy of HIV from the perspective of the actors, as it focuses the way people interpret and give meaning to their experiences and the world in which they live. It approaches social reality from a holistic perspective, trying to explain, describe and understand people's discourses on a particular social phenomenon [41]. In brief, seeking the meaning of phenomena is the main function of "the so-called qualitative" [42].

A qualitative methodology is equipped with multiple data collection or production procedures that share common aspects, such as the understanding of social phenomena [43] or the centrality of discursive practices and discourse analysis [44]. However, each data collection method offers a particular type of information. Multiple procedures exist for collecting qualitative data. Some of the most representative techniques of the qualitative social research methodology perspective, which can be very useful for approaching the HIV phenomenon, are the following: qualitative interview, focus group, life history and participant observation. It is worth noting that, like the rest of the techniques for collecting and analyzing information on research, these techniques ensure the confidentiality and privacy of the respondents to the extent that the information is treated anonymously and not personalized. Such techniques are usually applied in cross-sectional studies.
