More than half of police officers responsible for determining the degree of risk in missing people cases have never read national guidelines on how to handle such cases, according to new research.
A similar number also say their training in deciding risk is inadequate, according to the findings of a report published today by Richard Smith and Dr Karen Shalev Greene from the Centre for the Study of Missing Persons at the University of Portsmouth.
Police sergeants are responsible for overseeing the initial stages of missing person investigations but in the police force examined for the research, 51% said they had not read Association of Chief Police Officers (Acpo) guidelines on assessing risk, and 49% had also not read the force's own guidance documents.
Dr Shalev Greene said: "Decision-making is all too often subjective and inconsistent. One police sergeant might judge the risk of a set of circumstances as high and another might judge the same circumstances as medium.
"The challenge for policing is to remove such subjective measures, or at least place them within a more objective framework that ensures when the power of hindsight is being applied, the decision still stands up to scrutiny.
"The cost to the missing person, to society and to the police of misjudging risk and then choosing the wrong tactics can't be overestimated."
Researchers surveyed 215 police sergeants in a large police force in England. All had been in a senior role for at least five years.
A university spokeswoman said: "The shortcomings highlighted included missing people might be being put in further jeopardy by having the risk to them and the wider public wrongly judged, the police risk losing public support if they assess risk wrongly and financially, the cost of misjudging risk is enormous.
"About 313,000 people were reported missing in England and Wales in 2011-12 and the cost of investigating them is equivalent to £400-600m a year, or 14% of the total annual police budget."
Dr Shalev Greene said: "The report raises the question that if officers aren't taking responsibility for reading key documentation, what else are they missing? And if their training is said to be ineffective, what other skills are they not being taught?"
She said the report also raised other concerns and added: "We need to understand what lies at the heart of an apparent lack of faith in senior leaders in relation to management of missing person investigations, and how to ensure guidance and best practice from the Home Office and College of Policing penetrates the organisation and reaches those on the 'shop floor'."
The report argues for police officers to adhere to a formal framework, such as the National Decision Model, when calculating risk.
The model is a tool all UK police forces are expected to use when making decisions, including those related to missing persons, firearms incidents, and public order command situations but the research highlights it is not yet being used consistently.
Mr Smith said: "The model is all about removing gut instinct and creating a method by which defendable decisions can be made. While gut instinct seems very valid in the heat of the moment, it may not stand up to scrutiny in coroner's court."
Among the report's other recommendations are that duty inspectors should be given 'ownership' of all missing people cases for the first 48 hours, passing the case to other duty inspectors between shifts, to allow for a genuinely critical review of the risk assessment at shift handovers.