Tuesday, October 14, 2025

Review of Weapons of Math Destruction: How Big Data Increases Inequality and Threatens Democracy by Cathy O'Neill

This book review was written by Eugene Kernes   

Book can be found in: 
Book Club Event = Book List (11/29/2025)
Intriguing Connections = 1) How Does Data Get Use, And Misused?, 2) The Style of Math,


Watch Short Review

Excerpts

“The math-powered applications powering the data economy were based on choices made by fallible human beings.  Some of these choices were no doubt made with the best intentions.  Nevertheless, many of these models encoded human prejudice, misunderstanding, and bias into the software systems that increasingly managed our lives.  Like gods, these mathematical models were opaque, their workings invisible to all but the highest priests in their domain: mathematicians and computer scientists.  Their verdicts, even when wrong and harmful, were beyond dispute or appeal.  And they tend to punish the poor and the oppressed in our society, while making the rich richer.” – Cathy O'Neill, Introduction, Pages 10-11

 

“Our own values and desires influence our choices, from the data we choose to collect to the questions we ask.  Models are opinions embedded in mathematics.  |  Whether or not a model works is also a matter of opinion.  After all, a key component of every model, whether formal or informal, is its definition of success.  This is an important point that we’ll return to as we explore the dark world of WMDs.  In each case, we must ask not only who designed the model but also what that person or company is trying to accomplish.” – Cathy O'Neill, Chapter 1: Bomb Parts: What Is a Model?, Page 26-27

 

“That’s a problem, because scientists need their error feedback – in this case the presence of false negatives – to delve into forensic analysis and figure out what went wrong, what was misread, what data was ignored.  It’s how systems learn and get smarter.  Yet as we’ve seen, loads of WMDs, from recidivism models to teacher scores, blithely generate their own reality.  Managers assume that the scores are true enough to be useful, and the algorithm makes tough decisions easy.  They can fire employees and cut costs and blame their decisions on an objective number, whether it’s accurate or not.” – Cathy O'Neill, Chapter 7: Sweating Bullets: On the Job, Page 126


Review

Is This An Overview?

Models are abstract representations of a process, used to make predictions.  Everyone has and uses models every day to form expectations for events, and then make a decision.  Models are simplifications of reality, with a variety of information left out.  Models are based on the choices of the people that make them.  Choices about what variables and data to include or exclude.  Choices that can have good intentions, but have negative consequences.  Choices that can code prejudice, bias, and misunderstanding into a model, into a software system.  Models are opinions embedded in mathematics.  Models can be used to improve society, but models can also be harmful.  Models can become weapons of math destruction.

 

Models that function well are those that use enough and as much data as possible, without trying to exclude data which does not conform to expectations.  Data that is relevant to what is trying to be understood.  Data that becomes used to update the model.  Models require feedback to correct for mistakes.  Without feedback, there is no method of learning from mistakes.  Models that seek to understand reality need to constantly change based on feedback received.  Models are based on past experiences, used to form expectations of the future.  Models need to change as the future is not necessarily like the past. 

 

What turns functional models into weapons of math destruction, is when the model is opaque, has scale, and does damage.  When models are opaque, such as when they are hidden from the public, and only accessible to a select few, the model losses access to feedback.  By hiding the details of what goes into the model, the model is difficult to question and disagree with.  The model camouflages human bias with technology.  What is coded becomes dependent on information that is accessible to being measured, rather than what is wanted and effective. 

 

Weapons of math destruction are models that embody their own reality, rather than search to understand reality.  The model defines reality, with the results being justified by code.  Success is based on who sponsored the model, for business or political reasons.  The models are not necessarily beneficial to the people the model is used on, even if the model is claimed to be beneficial to those the model is used on.  When the model does harm on a massive scale, the human victims are held to a higher standard of evidence than the model is.  Harm is deemed more acceptable when the decision was validated by a mathematical model, even though the model was coded by humans with an intention. 

 

Caveats?

Even as this book is based on math, there is no need for a mathematical background to understand the content.  There is a lack of a technical explanation for models, nor an explanation for how the weapons of math destruction were formed.  The book is based on examples of when the models do harm on a massive scale.  There are few references to when models can be useful.  As models are coded with a human bias, the author is a human who wrote the book with a bias, revealed by political decisions and examples.   


Questions to Consider while Reading the Book

•What is the raison d’etre of the book?  For what purpose did the author write the book?  Why do people read this book?
•What are some limitations of the book?
•To whom would you suggest this book?
•What are models?
•How to use statistics to experiment? 
•What are Weapons of Math Destruction (WMDs)?
•What evidence does a human need compared to a WMD?
•What is success for a model?
•What is Moneyball?
•What are ads? 
•What is the broken windows study? 
•What are financial WMDs?
•What are educational WMDs? 
•What are employment WMDs?
•What are labor market WMDs?
•What are incarceration WMDs?
•How can WMDs be used by politicians? 


Book Details
Publisher:               Crown [Penguin Random House]
Edition ISBN:         9780553418828
Pages to read:          202
Publication:             2016
1st Edition:              2017
Format:                    eBook 

Ratings out of 5:
Readability    5
Content          5
Overall          5