Government policy is to build on evidence of what works. So, we conduct randomised controlled trials, we ‘nudge’ citizens, and we evaluate policies to recover evidence of what does or does not work. No one denies that the more you know the better; but how do you acquire knowledge? More importantly what constitutes knowledge?
We ‘know’ facts and believe explanations from many sources. We draw on research, political and legal knowledge. We check out statistics and labour over government data but what we do not do is draw systematically on experiential knowledge. Experience refers to the practical knowledge about the world amassed by individuals in an organisational and work context. Such knowledge is invariably in play. It involves selective retelling of the past to make sense of the present. It is used to explain past practice and events and to justify present activity and recommendations for the future. It is the central characteristic of a craft.
What happens when research-based knowledge bumps into experience and associated craft? It becomes part of the mix. The starting point is experience. Take the example of the police. Officers draw on the collective and individual experiences of other officers; on their stories. They ‘phone a friend’ and employ their knowledge of the local area. The emphasis falls on practice because they believe the shared knowledge of practitioners is of more value than the evidence. They talk about common sense, judgement, and ‘on the street’ experience. Police officers acknowledge that anything that can assist them in doing their job more effectively is welcome but they are more likely to embrace the practical. If they go to ostensibly objective data they will use their experience to interpret it and assess its usefulness. Their experience will construct the facts and explanations; that is, the evidence they will use.
Officers do not rely only on experience. They weave together knowledge from any available and relevant sources. Too often the different kinds of knowledge are set up as opposites; research-based versus craft knowledge. Demonstrably the police draw on any source of information available to them, and use their experience to determine the information they will act on. The choice is dictated by availability. Is there any research-based knowledge? If there is no research based knowledge (and we know that the research base is currently limited), then experience is all there is. Its use is both essential and inevitable.
Evidence-based policing persists because it provides the legitimating rationale for decisions made by other means. The imprimatur of science is used to legitimise essentially political decisions. Of course, there are policy contexts that are not politicised. Of course, some evidence is better founded and more relevant for some policies than others. And let us not forget, sometimes if not often, there is rational, scientific evidence available. But much evidence-based policing takes place in charged organisational and political contexts that ensure the data are always incomplete, always uncertain, and always ambiguous. So, the meaning of evidence is never fixed, it must be constantly won. By itself, evidence-based knowledge is not enough. We need the partisans arguing for scientific evidence but we need also other types of knowledge. Craft knowledge, political knowledge, and research-based knowledge, all warrant a place at the table. These several strands need to be woven together. Craft knowledge not only needs to be treated as evidence in this weaving, but we need to recognise that it provides also the basis for choosing between the available sources of evidence.
Experience may be a dirty word to the partisans of science, but it is essential given both the limits to, and lack of, social science knowledge.