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.

Related Articles


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 October 25, 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 October 25, 2014).

Share This



More Science & Society News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
WHO: Millions of Ebola Vaccine Doses by 2015

WHO: Millions of Ebola Vaccine Doses by 2015

AP (Oct. 24, 2014) The World Health Organization said on Friday that millions of doses of two experimental Ebola vaccines could be ready for use in 2015 and five more experimental vaccines would start being tested in March. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Microsoft Riding High On Strong Surface, Cloud Performance

Microsoft Riding High On Strong Surface, Cloud Performance

Newsy (Oct. 24, 2014) Microsoft's Q3 earnings showed its tablets and cloud services are really hitting their stride. Video provided by Newsy
Powered by NewsLook.com
EU Gets Climate Deal, UK PM Gets Knock

EU Gets Climate Deal, UK PM Gets Knock

Reuters - Business Video Online (Oct. 24, 2014) EU leaders achieve a show of unity by striking a compromise deal on carbon emissions. But David Cameron's bid to push back EU budget contributions gets a slap in the face as the European Commission demands an extra 2bn euros. David Pollard reports. Video provided by Reuters
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:

Strange & Offbeat Stories


Science & Society

Business & Industry

Education & Learning

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