Borrowed from anthropology, an etic view of culture is the perspective of an outsider looking in. An emic view of culture is ultimately a perspective focus on the intrinsic cultural distinctions that are meaningful to the members of a given society, often considered to be an ‘insider’s’ perspective.

Knife crime is a complex social problem. It is a symptom of a toxic environment which creates both perpetrator and victim. An understanding of those environments, often only possible through emic analysis, is crucial in tackling the problem.

Government spending cuts over recent years have seen a reduction in police numbers, the closing of youth centres, increased unemployment (particularly in vulnerable areas), and a drop in mental health services.

Some analysts argue that the economic policy of austerity cuts is helping to drive people toward crime, including vulnerable young people who had been helped by social services. Other analysts argue that blaming violent crime on reductions in the number of police goes far beyond the available evidence.

Once the number of people implicated in knife crime (and associated behaviours) reaches a certain level we can describe it as an epidemic. Threshold models help us confirm epidemics and assign appropriate control measures.

The models - similar to those used to understand the spread of disease - also help us understand the behaviour of groups, particularly when the collective behaviour of the groups does not match up with the preferences of individuals within that group. For example, an individual in a group may not actually want to carry a knife, but the collective group dynamics mean that they choose to do so anyway.

Sociological research suggests that interventions seeking to reduce knife crime should pay attention to one of the main reasons for carrying a knife: fear of victimisation and the resultant beliefs that knives are a source of protection against victimisation.

Fear of victimisation is a very real fear for many people, the origins of which may be complex. Such fears need to be taken seriously, especially in light of research which shows carrying a knife actually increases rather than decreases a person’s risk of victimisation.

The prisoner’s dilemma helps us understand what governs the balance between competition and cooperation. Weapons amnesties trade upon this idea. If everyone hands in their weapons, then everyone is better off. If some people choose to hold onto their weapons (i.e. do not give them up) then they are safer at the expense of those who do.

This concept lies at the heart of knife crime. You get a knife to protect yourself because of the knives around you, and you will only give your knife up if that’s what everyone else does. This is further complicated by the fact that you do not know for certain whether those around you have actually handed in their weapons or not.

Bayesian statistics are a particular approach to applying probability to statistical problems. It provides us with mathematical tools to update our beliefs in light of new data or evidence. A Bayesian analysis estimates how likely your hypothesis is, from your data, weighted a little bit with your assumptions.

Knife crime data can be used in a number of ways e.g. forecasting London neighbourhoods most likely to suffer a fatal stabbing in the following year. Data is only useful when it’s interpreted well, and a Bayesian approach is one useful way of doing this.

System maps allow us to create robust, non-linear theories of change that incorporate a variety of reinforcing and balancing loops (as well as time delays) to convey the true complexity of a change we are seeking to make.

Modelling knife crime is extremely difficult due to the complex dependencies, competitions, relationships, and other interactions between different people and groups involved in the problem. Systems mapping is a useful method for doing this.

Qualitative interviews are different from surveys in that they aim to let the respondent tell their own story on their own terms - though interviewers will have necessary topics to cover, questions to ask, and areas to probe.

There are many nuances to interviews. For example, knife crime is a highly emotive problem, and interviewers will need to be sensitive to that ethical dimension, ensuring the interviewee appreciates what the research is about, its purposes, and that their answers will be treated confidentially.

Originating in India, the parable of the Blind Men and an Elephant illustrates the idea that we each create our own version of reality from limited experience and perspective. This can lead to overreaching misinterpretations. It is easy to be seduced by the “rightness” of our views; by gathering data about knife crime from different perspectives, we get a better sense of the whole picture and can make more robust decisions.

A psychologist’s perspective on knife crime is likely to be different to that of a politician’s (and so on). Only through interdisciplinarity, collaboration, and communication are we able to gain a fuller understanding of the problem.

Striking a balance between keeping people safe and maintaining the trust and confidence of communities requires constant review and careful consideration. Misused, it can lead to increased community tensions and mistrust of police.

A lack of trust in the police can potentially lead victims to becoming perpetrators, as they use violence to seek revenge rather than relying on police procedures. Stop and search powers have also been linked to suspicion and increasing levels of distrust among BAME communities.