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Outcomes of evaluations of PEACE

Continuing the critical look at the science of training in investigative interviewing.

The outcomes of evaluations.

Outcomes of evaluations

As highlighted in a previous Blog (Evaluations of PEACE), there have been very few evaluations of the PEACE model, and those studies can be classified on two dimensions: type of evaluation and sample type.

Some of the evaluations have provided overall assessments on all five phases of PEACE training (which is probably not a good idea, see Evidence-based investigative interviewing), whilst others have restricted their focus to specific phases. Whilst many of the evaluations used rating scales based on those developed by Clarke and Milne (2001), there are some methodological variations that hinder the full integration of findings. To aid comprehension, the outcomes of the evaluations will be presented as ‘ratings’ (see Scott et al., 2015). These ratings include:

• Less than adequate (poor)

• Adequate (neutral)

• Skilled (good)

Assessing the five phases of PEACE

Preparation and planning:

Studies have consistently found the skills of PEACE trained interviewers to be adequate. That is, the performance of trained officers was largely comparable to that of untrained officers.

Engage & Explain:

Skills in this phase have largely been found to be adequate or less than adequate.


Skills in this phase have largely been found to be adequate, with some assessments showing skilled performance for eliciting free recall, but less than adequate skills in identifying topics.


Skills in this phase have largely been found to be less than adequate.


Skills in this phase have largely been found to be adequate or less than adequate.

Reviewing the evidence

The first evaluation (McGurk et al., 1993) had suggested that PEACE model training in interviewing had some positive effects on practical skills and knowledge. However, the next assessment (of all five phases) by Clarke and Milne (2001) concluded that performance was only adequate. No major differences were found between interviews conducted by untrained and trained officers, with the sole exception that interviews by trained officers were (on average) about five minutes longer (a similar finding was identified in New Zealand; Cunningham, 2010).

Clarke and Milne (2001) suggest that while “PEACE training has had little impact” (p.2) it is possible that even untrained officers may have been familiar with PEACE, even in the absence of formal training. In other words, the experimental protocol lacked scientific rigour: the control and experimental groups were not independent.

To further complicate this problem, Scott et al. (2015) report that even newly recruited (i.e., untrained) police officers in Australia use many components of the PEACE approach. This suggests that many of the aspects of PEACE are intuitive (seemingly a positive finding), but it then raises questions as to why many of the other evaluations described here have found that trained officers show less than adequate skills.

Where positive findings have been observed the differences between trained and untrained groups are often attributable to the performance of a small number of skilled interviewers. For example, in a non-police study, Walsh and Milne (2008) found that the performance of three-quarters of the trained officers was indistinguishable from that of the untrained officers. In other words, training benefited only one-in-four.

Walsh and Milne (2008) suggest that the poor skills transference of training may be because:

• The courses contain too much content.

• Interviewers regress to previous habits when they return to the workplace.

• There is a lack of supervisory support for trained interviewers (particularly as PEACE interviews take longer, with no obvious investigative benefit).

Does PEACE work?

There is remarkably little evidence to show that training police officers in the PEACE model brings any clear benefits. As a consequence, supporters of PEACE training have tended to emphasise essentially unverifiable benefits, such as it reducing the likelihood of miscarriages of justice. As no major miscarriages of justice (in the UK at least) post-PEACE have come to light, this is cited as evidence that training has brought about a cultural/ethical shift in interviewing. While this may be true, it is clearly a case of ‘moving the goalposts’ and is logically problematic: an absence of evidence cannot logically be used in favour of a claim.

What had begun as a set of specific, testable claims, has drifted into a set of unverifiable beliefs. As things currently stand, like the Reid Technique, PEACE lacks scientific support. That shortcoming needs to be addressed. It beggars belief that the last major evaluation of interviewing training with police officers was conducted almost 20 years ago and that in Australia the model has never been properly evaluated.

Key points

  • Evaluations of PEACE largely show that training has limited effect on operational practice; some evaluations suggest training impedes subsequent performance.

  • The strength of belief in PEACE is not justified by the scant evidence base.

  • PEACE was designed for the UK and requires adaption (and testing) before adoption in other countries.


Clarke, C., & Milne, R. (2001). National evaluation of the PEACE Investigative interviewing course. Home Office.

Clarke, C., Milne, R., & Bull, R. (2011). Interviewing suspects of crime: The impact of peace training, supervision, and the presence of a legal advisor. Journal of Investigative Psychology and Offender Profiling, 8(2), 149-162.

Cunningham, S. (2010). Evaluation of the implementation of investigative interviewing training and assessment (Level 1) final report.

Kim, J., Walsh, D., Bull, R., & Bergstrøm, H. (2017). Planning ahead? An exploratory study of South Korean investigators’ beliefs about their planning for investigative interviews of suspects. Journal of Police and Criminal Psychology.

McGurk, B. J., Carr, M. J., & McGurk, D. (1993). Investigative interviewing courses for police officers: An evaluation. Police Research Series Paper 4. Police Research Group, The Home Office.

Scott, A. J., Tudor-Owen, J., Pedretti, P., & Bull, R. (2015). How intuitive is PEACE? Newly recruited police officers' plans, interviews and self-evaluations. Psychiatry, Psychology and Law, 22(3), 355-367.

Walsh, D., & Bull, R. (2010a). Interviewing suspects of fraud: An in-depth analysis of interviewing skills. Journal of Psychiatry and Law, 38(1-2), 99-135.

Walsh, D., & Bull, R. (2010b). What really is effective in interviews with suspects? A study comparing interviewing skills against interviewing outcomes. Legal and Criminological Psychology, 15(2), 305-321.

Walsh, D., & Bull, R. (2012). How do interviewers attempt to overcome suspects' denials? Psychiatry, Psychology and Law, 19(2), 151-168.

Walsh, D., & Milne, R. (2008). Keeping the PEACE? A study of investigative interviewing practices in the public sector. Legal and Criminological Psychology, 13(1), 39-57.

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Blog 09 Outcomes of evaluations of PEACE
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