Featured Research

from universities, journals, and other organizations

Just A Numbers Game? Making Sense Of Health Statistics

Date:
October 13, 2008
Source:
Association for Psychological Science
Summary:
Health statistics fill today's information environment, but even most doctors, who must make daily decisions and recommendations based on numerical data, lack the basic statistical literacy they require to make such decisions effectively. A major new report in Psychological Science in the Public Interest shows that statistical illiteracy is a significant problem having widespread negative impact on healthcare and society.

Presidential candidates use them to persuade voters, drug companies use them to sell their products, and the media spin them in all kinds of ways, but nobody - candidates, reporters, let alone health consumers - understands them.

Health statistics fill today’s information environment, but even most doctors, who must make daily decisions and recommendations based on numerical data - for instance, to calculate the risks of a certain drug or surgical intervention, or to inform a patient of the possible benefits versus harms of cancer screening - lack the basic statistical literacy they require to make such decisions effectively.

A major new report shows that statistical illiteracy is a significant problem having widespread negative impact on healthcare and society. The authors of the report are an international and interdisciplinary team of psychologists — Gerd Gigerenzer and his colleagues Wolfgang Gaissmaier and Elke Kurz-Milcke at the Max Planck Institute for Human Development and Harding Center for Risk Literacy, Berlin, Germany — and physicians — Lisa M. Schwartz and Steven Woloshin at Dartmouth Medical School.

The problem of statistical illiteracy in health has two sides to it, according to Gigerenzer and his team. It is a combined problem caused by the misleading or confusing ways statistics are ordinarily presented in health communication, coupled with a lack of statistical thinking skills among consumers of health information.

The combination can be explosive. A mid-1990s report in Britain showed that new oral contraceptive pills posed a twofold (or 100%) increased risk of blood clots led to a mass panic among women, who opted to stop using this form of birth control as a result. There were an estimated 13,000 more abortions in England and Wales in the year following the report, due to the pill scare. Had the public been informed that the absolute risk with the new pills only increased from 1 in 7,000 women having a blood clot to 2 in 7,000, this panic would not have occurred, and the UK National Health Service would have been saved an estimated $70 million.

It is all too common for health statistics to be presented in terms of relative risks, which are generally large numbers and thus are easily used to capture people’s attention. Relative risks (“a 100% increase”) are very misleading, however, when important facts like base rates are left out. Absolute risk information (like “1 in 7,000”) is much more understandable, and less easy to sensationalize or spin in misleading ways, yet is too often absent from health coverage in the media, pharmaceutical advertising, and even medical journals.

Physicans are not immune. The authors of the report cite several startling studies showing the inability of doctors to accurately interpret data from cancer screenings or other test results, when the data were presented in the typical form of conditional probabilities. For example, when presented with conditional probabilities, a group of experienced physicians was unable to accurately estimate the chances a patient with a positive test result actually had colorectal cancer, given the known sensitivity and false-positive rate of the test used (estimates they gave ranged from a 1% to a 99% chance of having cancer, with most guessing around 50%). Most physicians gave the right answer (a less than 10% chance) when the data were presented in the more transparent form of natural frequencies.


Story Source:

The above story is based on materials provided by Association for Psychological Science. Note: Materials may be edited for content and length.


Journal Reference:

  1. Gigerenzer et al. Helping Doctors and Patients Make Sense of Health Statistics. Psychological Science in the Public Interest, 8 Oct 2008 DOI: 10.1111/j.1539-6053.2008.00033.x

Cite This Page:

Association for Psychological Science. "Just A Numbers Game? Making Sense Of Health Statistics." ScienceDaily. ScienceDaily, 13 October 2008. <www.sciencedaily.com/releases/2008/10/081010172449.htm>.
Association for Psychological Science. (2008, October 13). Just A Numbers Game? Making Sense Of Health Statistics. ScienceDaily. Retrieved August 22, 2014 from www.sciencedaily.com/releases/2008/10/081010172449.htm
Association for Psychological Science. "Just A Numbers Game? Making Sense Of Health Statistics." ScienceDaily. www.sciencedaily.com/releases/2008/10/081010172449.htm (accessed August 22, 2014).

Share This




More Science & Society News

Friday, August 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Bank of America's $17 Bln Settlement

Bank of America's $17 Bln Settlement

Reuters - Business Video Online (Aug. 21, 2014) Bank of America's settlement is by far the largest amount paid by big banks facing mortgage securities probes. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Cadavers, a Teen, and a Medical School Dream

Cadavers, a Teen, and a Medical School Dream

AP (Aug. 21, 2014) Contains graphic content. He's only 17. But Johntrell Bowles has wanted to be a doctor from a young age, despite the odds against him. He was recently the youngest participant in a cadaver program at the Indiana University NW medical school. (Aug. 21) Video provided by AP
Powered by NewsLook.com
Families Can Now Ask Twitter To Remove Photos Of Deceased

Families Can Now Ask Twitter To Remove Photos Of Deceased

Newsy (Aug. 20, 2014) In the wake of a high-profile harassment case, Twitter says family members can ask for photos of dying or dead relatives to be taken down. Video provided by Newsy
Powered by NewsLook.com
Reasons Why Teen Birth Rates Are At An All-Time Low

Reasons Why Teen Birth Rates Are At An All-Time Low

Newsy (Aug. 20, 2014) A CDC report says birth rates among teenagers have been declining for decades, reaching a new low in 2013. We look at several popular explanations. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins