STAGE 3. Defining the population and objectives

What steps should be completed?

STEP 1: Define the population

The population of an intervention is integrated by individuals, groups (or other units) with common characteristics relevant to the intervention, such as age, gender, origin, culture, values, territory, education, work or social circumstances, among others.

When designing an intervention to improve people's health, it is reasonable to benefit as many people as possible. However, reaching more people does not necessarily mean achieving more changes. In fact, when defining the target population of any intervention, it is best to establish priority criteria, specify their characteristics very well and be as realistic as possible. In this task, the information gathered in the previous phases of needs assessment and feasibility analysis will be of great help. Especially useful is, information on the individual and social consequences of drug consumption, the current level of consumption, the risk factors and protection factors present in the population, the level of knowledge of the problem that the population has, the possibilities the population has to accessing the programme, as well as their level of motivation to engage in a future intervention.

Also, exploring the most appropriate time to implement an intervention, is one of the decisions that have to be made when planning. Considering the population needs, there are more favorable moments than others for acquiring or changing behaviors. These moments are usually associated to some vital experiences, such as having suffered a health problem (an illness) or a vital change (such as becoming pregnant). In these circumstances, people tend to focus on taking better care of themselves and are more receptive to messages related to their lifestyle and health. Furthermore, consistent research findings show how some circumstances place people in conditions of greater vulnerability, such as the moments of developmental transition (for example, the transition from school/childhood - to secondary education/adolescence, facing unemployment, and so on); being the age immediately prior to those phases of maximum risk, the ones when the risk of developing problems associated with drugs is higher. Therefore, these vital phases deserve special attention when developing interventions. Likewise, interventions made in the stages prior to changes, tend to have a greater impact than later interventions.

The definition of the target population will completely determine the objectives and strategies for action. Thus, an intervention aimed for drug users is likely to pursue either cessation of use or harm reduction objectives, whereas it is likely that the purpose of an intervention aimed at non-users may be focusing on the preventing or delaying the onset of drug use. In both cases it is possible that, in order to reach the target population of the intervention, it may be necessary to involve people who provide access to this target population. Therefore, in some drug demand reduction interventions, two types of population are differentiated: the target population and the intermediary population. This differentiation is due to the fact that, often, the access, knowledge, relationship and influence that the intermediary population has with the target population, facilitates the expected behavioral changes among the targeted group. The nature of each intervention will determine whether this distinction is necessary and also whether it is relevant to incorporate, or not, more than one intermediary population to achieve changes in the target population. For example, in a project targeting children, families could be an intermediary population. We can differentiate between the two types of population by answering the questions: What population is expected to change as a result of the intervention? (target population) and which population will bring about and/or facilitate those changes? (intermediary population). However, the distinction between these two populations is only necessary when the intervention involves both groups. If the intervention only targets one population group (even if this is the intermediary), it will be called the target population. This has to be considered in order to unify criteria, so the word target population always appears in the planning protocols.

Finally, it should be highlighted that the population selected will absolutely determine the intervention approach. Thus, for example, there are different preventive interventions depending on the degree of exposure to the risk factors and the protection factors of the population: universal prevention, selective prevention and indicated prevention. +

In summary, the essential information for defining the target population is to obtain quality information about its individual, sociodemographic and social characteristics. +