Tim Hardford – watercress words by Dr Aletha

updated June 12, 2025

I reviewed a journal article about breast cancer, and as most medical articles do, it started with statistics.

Before the COVID-19 pandemic, you probably weren’t too familiar with the medical science of epidemiology, which is all about statistics.

Epidemiology is the branch of medical science that investigates all the factors that determine the presence or absence of diseases and disorders.
National Institutes of Health

Statistics help us understand what has happened, what is happening, and what may or will happen. Statistics can help determine how something happened.

Epidemiology provides information that can be used to change outcomes in health and disease. Those outcomes may involve life or death.

Health data doesn’t help us much if it stays in medical journals or textbooks. Physicians and other healthcare clinicians use it to counsel patients and make medical recommendations about preventive care, diagnosis, and treatment of diseases.

How doctors use statistics to help patients

You might say we use them as “talking points” to convince people to do things we believe will help them and to avoid doing things we think might hurt them. You’ve seen the same thing happen when public health officials make recommendations about COVID-19 suppression. So a doctor might

recommend you do something -get a mammogram or wear a mask

a mammogram image — a mammogram revealing a breast cancer image source- National Library of Medicine, Open-i

caution you against doing something -smoking cigarettes or gathering in crowds

No Smoking sign with pumpkins — Ask your doctor about ways to help you stop smoking.

encourage a behavior-wearing sunscreen or keeping 6 feet distance

all based on knowing the epidemiology of breast, lung, and skin cancers, and COVID-19 based on statistics.

Breast cancer incidence and risk

So getting back to the breast cancer article, I think many women overestimate their risk of getting and dying from breast cancer. According to the article, in the

past 5 years, 2.3 million cases of breast cancer

in women have been diagnosed in the United States (breast cancer does occur in men but the number is so low it does not change this total significantly)

The mortality rate for breast cancer is 20 deaths/100,000 women. The most recent number for deaths in 1 year is 42,000. (United States)

chance of developing breast cancer by age 70-National Cancer Institute — Source: National Cancer Institute (NCI)

The majority of women have NORMAL BRCA.

COVID-19 by comparison

There were 27 million cases of COVID-19 February 2020-February 2021

diagnosed in both men and women in the United States. (And many experts suspect that thousands of cases have gone unrecognized.)

The mortality rate for COVID-19 then was approximately 134/100,000 people. The current number of deaths in the past year is 460,000. (These numbers are compiled by Johns Hopkins University and are current as of the original published day of this post)

WHO, the World Health Organization, reports that 2.3 million new cases of breast cancer occurred last year, while in less than a year there have been 105 million diagnosed cases of COVID-19.

Did these numbers surprise you?

Did they cause you to change your mind about something?

Will you change behavior based on these numbers?

What does it matter?

Healthcare professionals use statistics to understand and predict health risks, then counsel their patients about maintaining health and preventing disease, disability, and early death. One way they do so is with screening tests, like mammograms, to detect early breast cancer when it is easier to treat. successfully.

a female physician talking to a male patient

Public health professionals do the same thing, but apply the knowledge to large populations of people, such as infants, children, adolescents, pregnant women, or the elderly. And sometimes to an entire neighborhood, town, state, or nation, as we’ve seen happen with the SARS-CoV-2 pandemic, recommending masking, social distancing, handwashing, and vaccination.

But when health, especially public health, becomes politicized, these “talking points” can be used to

inflame rather than inform
manipulate not motivate
confuse rather than comfort
cause panic instead of instilling peace.

This is more likely to happen when we don’t understand the statistics and reasoning behind the recommendations. I believe much of the misinformation shared on social media unintentional, but stems from misunderstanding of the intended message.

The Data Detective: Ten Easy Rules to Make Sense of Statistics

This is the title of a new book by Financial Times columnist Tim Harford in which he tries to answer the question

Why do we believe what isn’t true?

In an interview by Erica Pandey, Harford encourages us to be curious and open-minded, and ask the right questions with a desire to understand. When you read or hear some new or disturbing information about any controversial topic, ask yourself if the teller is trying to make you smarter or trying to win an argument.

(AXIOS Today podcast February 5, 2021)

(This is an affiliate link, meaning it may pay a commission to this blog is a sale occurs.)

If we can toss aside our fears and learn to approach them clearly—understanding how our own preconceptions lead us astray—statistics can point to ways we can live better and work smarter.
The Data Detective listing on Amazon

My 5 guidelines for making sense of information

RECOGNIZE any bias, inconsistencies, contradictions; does it confirm what you already know? If not, why not? What is it trying to make you believe?
RESEARCH other sources and other media, what do they say about the topic, and are they credible?
REVIEW all the information you find trustworthy; do you have all the information you need to make a conclusion?
RECONSIDER when new information becomes available or circumstances change; if significant, you may need to start the process all over.
REMEMBER almost everything is subject to reinterpretation; as the numbers change, so may the conclusions. Statistics give us a chance to learn and understand, but aren’t the best way to prove a point or to win arguments .

final thoughts-Know Your Chances

(an affiliate link)

How to see through the hype in medical news, ads, and public service announcements

be a healthy skeptic. That doesn’t mean you have to be a cynic, simply disbelieving all the health messages you hear.

Instead, it means approaching messages critically: looking out for—and seeing through—common tactics used to exaggerate the importance of health problems or actions you can take to address them.

These tactics include emphasizing unimportant outcomes, avoiding numbers, or presenting statistics in ways that make them seem more important than they really are.

Know Your Chances: Understanding Health Statistics, by Steven, Woloshin, Lisa M. Schwartz, and H. Gilbert Welch. © 2008 by the Regenets of the University of California. Published by the University of California Press. (Read free at this link)

Exploring the HEART of Health

Find up-to-date information about breast cancer from The American Cancer Society and in Breast Cancer Clear & Simple (an affiliate link)

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Tag: Tim Hardford

5 steps to understand statistics about health risks

updated June 12, 2025