A positivist approach provides us with a research method that theoretically allows us to collect objective facts about the world just by observing it (Chalmers 2013:3). The positivist approach also give us hope about possibilities of using this fact to influence the society in a certain direction. For example, by collecting facts about crime, and using this fact to discourage crime. A prerequisite for such a thing to work, however, is that the collected facts is objective and reflects the actual circumstances (Chalmers 2013:3-4), and is valid for the type of crime we studied and designed to reduce. If we study crime in different neighborhoods and see that in neighborhoods, where there is a more widespread collaboration and better connection between the neighbors, have lower crime rates, then we can use this knowledge to try to establish cooperation and enhance the connection between neighbors in areas with higher crime rates, and thus lowering crime rates in the area.
However, this is something that does not always work when the social world does not always respond to actions in the same way everywhere. The positivist approach may thus be a way to begin to understand how reality works, though there are often many more variables to take into consideration. This means that the observed facts can be misleading and incomplete atmight have to be revised (Chalmers 2013:23). And our efforts may fall flat when applied to a different social worlds (in this example, another type of neighborhood) which do not have the same social structures that the previously observed neighborhood (Sayer 2000:15).
A positivist approach can thus serve as a tool to collect social facts, and give us clues about how this social facts can be applied to society. Positivistic facts, however, is not complete, and in order to make use of the collected knowledge, we may have to use other ways to understand the social reality, and understand whether we can make use of our positivist understanding to influence other social units. We might then need to to turn to other approaches than the positivist approach.
Chalmers, Alan F. (2013). What is this thing called science?. 4th ed. Maidenhead: Open University Press/McGraw-Hill Education
Sayer, Andrew (2000). Realism and social science. London: SAGE