5 steps to understand statistics on cancer, COVID-19, and other health risks

But numbers need context. Statistics help us understand what has happened before, what is happening now, and what may or will happen in the future. And not only what, but how and why. Then we can act to change the outcome. And sometimes those outcomes involve life or death.

screenshot of coronavirus statistics

Recently I reviewed a journal article about breast cancer, and as most medical articles do, it started with statistics. You’ve been hearing and reading a lot of statistics about COVID-19 the past year; every television news report about the pandemic starts with the numbers -how many new cases, how many total cases, how many vaccinated, and unfortunately how many deaths.

Before the pandemic you probably weren’t too familiar with the medical science of epidemiology which uses lots of 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

But numbers need context. Statistics help us understand what has happened before, what is happening now, and what may or will happen in the future. And not only what, but how and why. Then we can act to change the outcome. And sometimes those outcomes involve life or death.

Health data doesn’t help us much if it just ends up in medical journals or textbooks. Physicians and other healthcare clinicians use it to counsel patients and make medical recommendations about preventive care, and diagnosis and treatments 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
Practice Social Distancing

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

Since the onset of the pandemic there are been

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 current mortality rate for COVID-19 is 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 published day of this post)

Photo by Anton Uniqueton on Pexels.com

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.

And this is more likely to happen when we don’t understand the statistics and reasoning behind the recommendations. I believe much of the misinformation that has been shared on social media is not intentional, but from misunderstanding of the message that was intended.

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 and perhaps disturbing information about the pandemic, cancer, or any other hot 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)

sharing the HEART of healthcare statistics

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

Dr Aletha

Author: Aletha Cress Oglesby, M.D.

As a family physician, I explore the HEART of HEALTH in my work, recreation, community, and through writing. My blog, Watercress Words, informs and inspires us to live in health. I believe we can turn our health challenges into healthy opportunities. When we do, we can share the HEART of health with our families, communities, and the world. Come explore and share with me.

4 thoughts on “5 steps to understand statistics on cancer, COVID-19, and other health risks”

  1. Thank you for sharing at #OverTheMoon. Pinned and shared. Have a lovely week. I hope to see you at next week’s party too! Please stay safe and healthy. Come party with us at Over The Moon! Catapult your content Over The Moon! @marilyn_lesniak @EclecticRedBarn Stay safe

    Liked by 1 person

  2. Thank you for sharing at #OverTheMoon. Pinned and shared. Have a lovely week. I hope to see you at next week’s party too! Please stay safe and healthy. Come party with us at Over The Moon! Catapult your content Over The Moon! @marilyn_lesniak @EclecticRedBarn


  3. Thank you Aletha. Each night I see our local statistics on COVID testing, infections, death, and vaccinations. They are hard to interpret and understand the significance of each number. It does help when they compare those numbers to things I am familiar with from the past, such as deaths from the flu or cancer. I have started paying more attention to the number of hospitalizations and the percent of ICU beds that are full. I can fully grasp the significance of those numbers. In the meantime, I wear my mask when I leave the house and avoid large gatherings, and of course, wash my hands!


    1. Thanks Christie, I suspected I’m not the only one who gets confused with statistics. There are even statistics about statistics. I’ve noticed more attention directed to hospitalizations and ICU usage, which I agree is easier to understand. My husband and I have both been vaccinated for COVID-19, but we still wear masks, wash hands, and avoid large gatherings; I’m pleased that you do too. Perhaps within a few months those won’t be necessary-although I hope we all keep washing our hands indefinitely.


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