Table Of Content“Complexity, wicked problems, big–data, and a growing body of police research are examples
of what chief executives must understand in today’s contemporary policing environment to be
successful. Mental Models can aid in the decomposition of these complexities. Dr. Mitchell’s
book is the first to amalgamate the concept of Mental Models and police decision-making
by providing a critical thinking framework for police leaders to follow in a pragmatic, easy to
follow format. Dr. Mitchell’s teachings will challenge the readers’ assumptions on how they
make decisions. As police leaders, it is time we move the needle forward and examine how we
make policy decisions in society’s name. This book is a bold step forward.”
Commander Chris G. Vallejo, Austin (TX) Police Department
“Dr. Renée Mitchell does an outstanding job of discussing her unique approach to utilizing
mental modeling to incorporate the use of data and research in the most important areas of the
policing realm – making it easily digestible for every reader. As police administrators, we must
ensure we are well-educated in the use of data in day-to-day decision-making. Renee outlines
this process – utilizing her twenty-one mental models to help strengthen police leadership – in
a simple yet progressive way. This is a must-read for every police leader!”
Chief Ken Clary, Bellevue Nebraska Police Department
“If there is one book on policing you should read it is this. It’s a well-worn phrase but seri-
ously, all police leaders and commissioners SHOULD read this. Renée has taken the content
of hundreds of insightful papers and books and distilled it into a relevant and page turning
guide to policing. She highlights pitfalls and opportunities, all with the intention of improving
the service we deliver. The problem with the Atlantic difference between the US and Europe
means the continued reference to math instead of maths which will drive the European
reader mad, but forgive the bad English and instead learn the lessons, some of which you
already know and some you won’t. There are three things that stand out to me; its relevance,
its objectivity and finally its writing style – the perfect fusion of an author that has her feet in
the world of policing and academia. I know Renée, and I have to say she is slightly crazy – but
nothing great ever comes from mediocrity and it takes someone like Renée to put together
something as good as this. The timing is perfect; the erosion of trust meets the opportunity
of empirical analysis. Renée quotes Ben Goldacre and I would do the same in motivating
people to read this: ‘anyone who is going to trade in numbers, and use them, and think with
them, and persuade with them, let alone lock people up with them, also has a responsibility
to understand them’. This book enables us to start doing just that.”
Alex Murray, Commander Metropolitan Police Service
Founder of the Society of Evidence-based Policing
“Dr. Renée Mitchell expertly blends her academic insights with her wisdom gained through
her career as a police officer to create this much-needed, easily accessible book. At a time when
there is a historic focus on the role and actions of police in America, Dr. Mitchell distills how
best to advance the profession in a simple, compelling framework: if you want to improve the
way police act, you first must improve the way they think.”
Maureen McGough, Chief of Staff NYU School
of Law Policing Project
“This book forces the reader to challenge everything they thought they knew about policing.
Have we really been asking the wrong questions? Have we incorrectly defined the problem?
Renee offers an insight only gained from experiencing policing as a cop, an academic, and as
a champion of evidence-based policing.”
Josh Young, Deputy Senior Vice President of Justice
Initiatives Center for Policing Equity
“Using robust evidence to enable operational and strategic decision making is a fundamental
component of modern policing, this book guides and supports police practitioners through
some of the challenges and significant opportunities that various disciplines of science presents
for policing, including the Mental Model focusing on Evidence Based Policing which is my
favourite. A fantastic read for inquisitive minds.”
Superintendent Bruce O’ Brien, Director of Evidence
Based Policing New Zealand Police
Twenty-one Mental Models
That Can Change Policing
This book goes beyond other police leadership books to teach practitioners how to think
about policing in a structured way that synthesizes criminological theory, statistics, research
design, applied research, and what works and what doesn’t in policing into Mental Models.
A Mental Model is a representation of how something works. Using a Mental Model frame-
work to simplify complex concepts, readers will take away an in-depth understanding of
how cognitive biases affect our ability to understand and interpret data, what empirical
research says about effective police interventions, how statistical data should be structured
for management meetings, and how to evaluate interventions for efficiency and effectiveness.
While evidence-based practice is critical to advancing the police profession, it is limited
in scope, and is only part of what is necessary to support sustainable change in policing.
Policing requires a scientifically based framework to understand and interpret data in a way
that minimizes cognitive bias to allow for better responses to complex problems. Data and
research have advanced so rapidly in the last several decades that it is difficult for even the
most ambitious of police leaders to keep pace. The Twenty-one Mental Models were synthe-
sized to create a framework for any police, public, or community leader to better understand
how cognitive bias contributes to misunderstanding data and gives the reader the tools to
overcome those biases to better serve their communities.
The book is intended for a wide range of audiences, including law enforcement and com-
munity leaders; scholars and policy experts who specialize in policing; students of criminal
justice, organizations, and management; reporters and journalists; individuals who aspire to
police careers; and citizen consumers of policing data. Anyone who is going to make decisions
about their communities based on data has a responsibility to be numerate and this book,
Twenty-one Mental Models That Can Change Policing: A Framework For Using Data and Research
For Overcoming Cognitive Bias, will help you become just that.
Renée J. Mitchell served in the Sacramento Police Department for twenty-two years and is
currently a Senior Police Researcher with RTI International. She holds a B.S. in Psychology,
an M.A. in Counseling Psychology, and an M.B.A., a J.D., and a Ph.D. in Criminology from
the University of Cambridge. She has taught and lectured internationally on evidence-based
policing and is best known for being the first policing pracademic to run a randomized con-
trolled trial. She was a Fulbright Police Research Fellow and is the co-founder and executive
committee member of the American Society of Evidence-Based Policing. She has two TEDx
talks, “Research Not Protests” and “Policing Needs to Change: Trust me I’m a Cop,” where
she advocates for evidence-based policing. She has published her research in the Journal of
Experimental Criminology, Justice Quarterly, and the Cambridge Journal of Evidence-Based Polic-
ing. Her books include Evidence Based Policing: An Introduction and Implementing Evidence-Based
Research: A How-to Guide for Police Organizations.
Routledge Series on Practical and Evidence-Based Policing
Books in the Routledge Series on Practical and Evidence-Based Policing disseminate
knowledge and provide practical tools for law enforcement leaders and personnel to protect
and serve the public and reduce crime. With an aim to bridge the “translation gap” between
frontline policing and academic research, books in this series apply sound scientific methods
as well as practical experience to make everyday police work safer and smarter. These books
are an invaluable resource for police practitioners, academic researchers, public policymak-
ers, and students in law enforcement and criminology programs to guide best practices in
all aspects of policing.
Police Misconduct Complaint Investigations Manual, 2nd Edition
Barbara Attard and Kathryn Olson
Guidelines for Investigating Officer-Involved Shootings,
Arrest-Related Deaths, and Deaths in Custody
Darrell L. Ross and Gary M. Vilke
Twenty-one Mental Models That Can Change Policing
A Framework for Using Data and Research for Overcoming Cognitive Bias
Renée J. Mitchell
Twenty-one Mental Models
That Can Change Policing
A Framework for Using Data and Research
for Overcoming Cognitive Bias
Renée J. Mitchell
First published 2022
by Routledge
605 Third Avenue, New York, NY 10158
and by Routledge
2 Park Square, Milton Park, Abingdon, Oxon, OX14 4RN
Routledge is an imprint of the Taylor & Francis Group, an informa business
© 2022 Taylor & Francis
The right of Renée J. Mitchell to be identified as author of this work has been asserted by
her in accordance with sections 77 and 78 of the Copyright, Designs and Patents Act 1988.
All rights reserved. No part of this book may be reprinted or reproduced or utilised in any
form or by any electronic, mechanical, or other means, now known or hereafter invented,
including photocopying and recording, or in any information storage or retrieval system,
without permission in writing from the publishers.
Trademark notice: Product or corporate names may be trademarks or registered trademarks,
and are used only for identification and explanation without intent to infringe.
Library of Congress Cataloging-in-Publication Data
Names: Mitchell, Renée J., author.
Title: Twenty-one mental models that can change policing: a framework for using data and
research for overcoming cognitive bias / Renée J. Mitchell.
Description: 1 Edition. | New York: Routledge, 2021. | Series: Practical and evidence-based
policing | Includes bibliographical references and index.
Identifiers: LCCN 2021009173 (print) | LCCN 2021009174 (ebook) | ISBN 9780367481476
(hardback) | ISBN 9780367480080 (paperback) | ISBN 9780367481520 (ebook)
Subjects: LCSH: Community policing. | Criminal justice, Administration of.
Classification: LCC HV7936.C83 M65 2021 (print) | LCC HV7936.C83 (ebook) |
DDC 363.2/3—dc23
LC record available at https://lccn.loc.gov/2021009173
LC ebook record available at https://lccn.loc.gov/2021009174
ISBN: 9780367481476 (hbk)
ISBN: 9780367480080 (pbk)
ISBN: 9780367481520 (ebk)
DOI: 10.4324/9780367481520
Typeset in Bembo
by KnowledgeWorks Global Ltd.
Access the Support Material: www.Routledge.com/9780367480080
To Mark, thank you for suffering through all my crazy pursuits and still
loving me despite them.
Anything, anytime, anywhere.
To Cole and Kyle, I love you fiercely. And no matter where you go and
what you do in life, please base your beliefs on empirical research.
Contents
Figures xii
Tables xiv
Acknowledgments xv
Prologue: The Shoulders of Giants xvi
Introduction: What is a Mental Model and How Does It Help Policing 1
PART I
How We Think
Mental Model #1: System 1 and System 2 9
Mental Model #2: Cognitive Biases 15
Mental Model #3: First Principles Thinking 23
The Mental Models in Practice I-Mental Models 1-3: System 1 and System 2,
Cognitive Biases, and First Principles Thinking 30
PART II
How We Think About Math
Mental Model #4: False Linear Thinking 35
Mental Model #5: Binary Percent Changes 41
Mental Model #6: Second Order Thinking 48
The Mental Models in Practice II-Mental Models 4-6: False Linear Thinking,
Binary Percent Changes, and Second Order Thinking 55
PART III
How Things Concentrate
Mental Model #7: The Pareto Principle 59
Mental Model #8: The Law of Crime Concentration 64
