Most published research findings may be false

August 29, 2005

"There is increasing concern that in modern research, false findings may be the majority or even the vast majority of published research claims," says researcher John Ioannidis in an analysis in the open access international medical journal PLoS Medicine.

In his analysis, Ioannidis, of the University of Ioannina School of Medicine, Greece, and Tufts University School of Medicine, United States, identifies the factors that he believes lead to research findings often being false.

One of these factors is that many research studies are small. "The smaller the studies conducted in a scientific field, the less likely the research findings are to be true," says Ioannidis.

Another problem is that in many scientific fields, the "effect sizes" (a measure of how much a risk factor such as smoking increases a person's risk of disease, or how much a treatment is likely to improve a disease) are small.

Research findings are more likely true in scientific fields with large effects, such as the impact of smoking on cancer, than in scientific fields where postulated effects are small, such as genetic risk factors for diseases where many different genes are involved in causation. If the effect sizes are very small in a particular field, says Ioannidis, it is "likely to be plagued by almost ubiquitous false positive claims."

Financial and other interests and prejudices can also lead to untrue results. And "the hotter a scientific field (with more scientific teams involved), the less likely the research findings are to be true," which may explain why we sometimes see "major excitement followed rapidly by severe disappointments in fields that draw wide attention."

In their linked editorial, the PLoS Medicine editors discuss the implications of Ioannidis' analysis. "Publication of preliminary findings, negative studies, confirmations, and refutations is an essential part of getting closer to the truth," they say.

Nevertheless, the editors "encourage authors to discuss biases, study limitations, and potential confounding factors. We acknowledge that most studies published should be viewed as hypothesis-generating, rather than conclusive."
-end-
Citation: Ioannidis JPA (2005) Why most published research findings are false. PLoS Med 2(8): e124.

CONTACT:
John P.A. Ioannidis
University of Ioannina, School of Medicine, Ioannina, Greece
Tufts University, School of Medicine, Boston, Massachusetts, U.S.A.
E-mail: jioannid@cc.uoi.gr

THE RELATED ARTICLE FROM PLoS Medicine:

Citation: PLoS Medicine Editors (2005) Minimizing mistakes and embracing uncertainty. PLoS Med 2(8): e272.

CONTACTS:

PLoS Medicine Editors

Barbara Cohen
bcohen@plos.org
+1-415-624-1206 Gavin Yamey
gyamey@plos.org
+1-415-624-1221

Public Library of Science
185 Berry Street, Suite 3100
San Francisco, CA 94107
U.S.A.

PLEASE MENTION PLoS Medicine (www.plosmedicine.org) AS THE SOURCE FOR THESE ARTICLES. THANK YOU.

All works published in PLoS Medicine are open access. Everything is immediately available without cost to anyone, anywhere--to read, download, redistribute, include in databases, and otherwise use--subject only to the condition that the original authorship is properly attributed. Copyright is retained by the authors. The Public Library of Science uses the Creative Commons Attribution License.

About PLoS Medicine

PLoS Medicine is an open access, freely available international medical journal. It publishes original research that enhances our understanding of human health and disease, together with commentary and analysis of important global health issues. For more information, visit http://www.plosmedicine.org

About the Public Library of Science

The Public Library of Science (PLoS) is a non-profit organization of scientists and physicians committed to making the world's scientific and medical literature a freely available public resource. For more information, visit http://www.plos.org

PLOS

Related Smoking Articles from Brightsurf:

Smoking rates falling in adults, but stroke survivors' smoking rates remain steady
While the rate of Americans who smoke tobacco has fallen steadily over the last two decades, the rate of stroke survivors who smoke has not changed significantly.

What is your risk from smoking? Your network knows!
A new study from researchers at Penn's Annenberg School for Communication found that most people, smokers and non-smokers alike, were nowhere near accurate in their answers to questions about smoking's health effects.

Want to quit smoking? Partner up
Kicking the habit works best in pairs. That's the main message of a study presented today at EuroPrevent 2019, a scientific congress of the European Society of Cardiology (ESC).

Smoking and mortality in Asia
In this analysis of data from 20 studies conducted in China, Japan, South Korea, Singapore, Taiwan and India with more than 1 million participants, deaths associated with smoking continued to increase among men in Asia grouped by the years in which they were born.

Predictors of successfully quitting smoking among smokers registered at the quit smoking clinic at a public hospital in northeastern Malaysia
In the current issue of Family Medicine and Community Health, Nur Izzati Mohammad et al. consider how cigarette smoking is one of the risk factors leading to noncommunicable diseases such as cardiovascular and respiratory system diseases and cancer.

Restaurant and bar smoking bans do reduce smoking, especially among the highly educated
Smoking risk drops significantly in college graduates when they live near areas that have completely banned smoking in bars and restaurants, according to a new study in the American Journal of Epidemiology.

How the UK smoking ban increased wellbeing
Married women with children reported the largest increase in well-being following the smoking bans in the UK in 2006 and 2007 but there was no comparable increase for married men with children.

Smoking study personalizes treatment
A simple blood test is allowing Vanderbilt University Medical Center (VUMC) researchers to determine which patients should be prescribed varenicline (Chantix) to stop smoking and which patients could do just as well, and avoid side effects, by using a nicotine patch.

A biophysical smoking gun
While much about Alzheimer's disease remains a mystery, scientists do know that part of the disease's progression involves a normal protein called tau, aggregating to form ropelike inclusions within brain cells that eventually strangle the neurons.

A case where smoking helped
A mutation in the hemoglobin of a young woman in Germany was found to cause her mild anemia.

Read More: Smoking News and Smoking Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.