Joint Decision Model for Investigators: Record Defensible Decisions

Every investigative decision can end up being examined later — by a court, a tribunal or an inspector. Whether to deploy a camera, whether online research has become systematic monitoring, whether a victim is entitled to enhanced rights. The question then is not only whether you got it right. It is whether you can show how you got there.A decision model gives you that structure. The one we recommend for investigators is the Joint Decision Model.

Where the JDM comes from

The Joint Decision Model is set out in the Joint Doctrine of JESIP — the Joint Emergency Services Interoperability Principles — for multi-agency working. The College of Policing says “The JDM is based on the police NDM” (College of Policing, decision models). Police readers will know the National Decision Model, which places the Code of Ethics at its centre and which the College describes as “the primary decision model for the police service”.

JESIP states: “Commanders should use the Joint Decision Model (JDM) to help bring together the available information, reconcile objectives and make effective decisions – together.” It was built for emergencies.

Our view at BDG is that the same five stages work just as well for everyday investigative decisions, especially where more than one organisation holds part of the picture. That is our training view, not JESIP guidance.

The five stages

Using it to record your rationale

The five stages give you a ready-made set of headings for any record — a notebook entry, a decision log, a surveillance application or a case file note.

•Information: what you knew at the time, where it came from, and what gaps remained. Note anything shared with or received from partner agencies.

•Threat and risk: the harm you identified, who was at risk, how serious and how likely, and the working strategy you adopted.

• Powers and policy: the legal power or authority you relied on, any relevant policy or code of practice, and why you were satisfied the threshold was met.

• Options: the options you considered, why you chose the one you did, and what you would do if circumstances changed.

• Action and review: what you did, when, and the outcome. Set a review date and record what triggered any change of approach.

You do not need to write “JDM” in your notebook. What matters is that the entry answers five questions: What did I know? What was the risk? What power did I use? What were my options? What did I do and why?

Train with BDG. To discuss decision-making and rationale-recording training for your team, see our investigation courses or email info@bdgtrainingconsultancy.co.uk. Read Edition 7 of The Investigator Bulletin in full at https://www.bdgtrainingconsultancy.co.uk/investigator-bulletin

Sources: JESIP, The Joint Decision Model (JDM), jesip.org.uk, College of Policing, APP National Decision Model (updated 24 January 2024), college.police.uk;

This article is a training and awareness summary and does not constitute legal advice , your own organisation’s policy and legal adviser take precedence.