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Making good decisions

Ensuring impartiality and recording investigative decisions.

First published
Conducting effective investigations

Investigators should ensure impartiality in:

  • deciding what constitutes a proportionate investigation
  • the way in which they listen to and evaluate the material provided by all victims, witnesses and suspects
  • how they gather and evaluate material
  • the assumptions they make relating to any aspect of the investigation

Investigators should record investigative decisions in a clear and objective way with supporting rationale.

This will support investigators to recognise, and take steps to mitigate, the adverse effects that a range of cognitive
biases can have on the mental shortcuts that people automatically use when trying to make sense of new information, make decisions, or take action.

Evidence summary

There was good evidence that biases (unconscious or conscious) can influence an investigation. There is consistent evidence that an initial hypothesis or initial belief in a suspect’s guilt significantly affects interpretation of further evidence and can lead to the seeking of evidence to confirm a hypothesis.

There is also evidence to suggest that officers’ perceptions of victim credibility and suspect blame may affect how they treat the victim and investigate the crime. Examples of this include having an impact on allocating resource to the case, the likelihood of arrest and pursuing all lines of enquiry.

The majority of the evidence supporting this guideline is taken from research into crimes that disproportionately affect women and girls, notably rape and domestic abuse. The evidence was limited on ways to tackle bias and there was mixed evidence on the impact of training on bias.

The committee felt that clearly recording decisions was critical to an effective investigation. The practice evidence supports this.

Empirical evidence
Practitioner evidence

Decision making and recording for impartiality

Investigators should use the national decision model and the Code of Ethics to help with decision making. In relation to the investigative process, officers have discretion at many decision-making points throughout the course of the investigation and they should feel empowered to make decisions.

Being impartial, mitigating one’s biases and recording decisions will support making justifiable, effective decisions that are proportionate, lawful, accountable, necessary and ethical. Different types of bias can have an impact on investigators’ decision making. Unconscious bias affects everybody’s decision making. It happens when we make quick decisions in ambiguous situations that, without us realising, may disadvantage particular groups of people.

Bias can also have an adverse impact on community confidence. See the Police Race Action Plan. Our biases are influenced by our background, culture and personal experiences. Confirmation bias is the tendency to process information by looking for, or interpreting, information that is consistent with one’s hypothesis or initial beliefs. Investigators should strive to be aware of, and to minimise, their own unconscious biases.

Ways to mitigate against biases include reflective practice, effective supervision and taking advice from colleagues, specialists and stakeholders.

Investigators from other organisations felt strongly that effective supervisory review and oversight (see Supporting the delivery of effective investigations) was crucial to mitigate the impact of biases on decision making and to ensure that investigators remain impartial in investigations.

Hints and tips – remaining impartial

Impartiality and mitigating biases can be enhanced by:

  • collaboration and supervision, so practitioners can work together to explore their decisions and the actions they take in investigations
  • using reflective practice on a regular basis, and capturing or recording reflections – reflective practice is the ability to reflect on one’s actions and decisions, and improve practice as a result
  • using reflective practice frameworks, such as the Betari Box framework and Gibbs’ Reflective Cycle, or using the competency and values framework (CVF)
  • sense checking decisions with colleagues and supervisors
  • analysis and understanding of overall incident patterns and trends
  • recording and reviewing decisions

Ensuring impartiality

A possible strategy to reduce confirmation bias in the investigation process is for investigators to be instructed to ‘consider the opposite’ during the identification and formulation of hypotheses in a criminal investigation. This may increase the numbers of hypotheses generated. There is no available evidence that training can eliminate unconscious bias. However, there is some evidence from clinical and educational settings to suggest that empathy training or interventions have the potential to mitigate bias.

The committee emphasised the importance of recording decisions clearly and objectively to support effective decision making. They felt that this helps investigators recognise the choices they make at each stage of an investigation and reflect on practice.

Having an investigation plan may support the recording of decisions and provide an auditable record of activity.
Investigators may also consider consistently using body-worn video (BWV) to assist with this. BWV could be used to record spontaneous decision making at the scene and may help emphasise the need to articulate thought processes throughout an investigation. Footage from BWV could also be used to review investigators’ decisions and the actions they take, to facilitate organisational learning and the sharing of good practice (Grossman L and others, 2015).


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