A study was conducted by John P.A. Ioannidis, MD, published in JAMA, Vol. 294, in order to try and understand how frequently highly cited studies are contradicted, or effects much lower than originally observed are found, as well as to discern whether specific characteristics are
associated with such refutations over time.
The author examined all original research studies published in 3 major general clinical journals, or high-impact-factor
specialty journals in 1990-2003 and cited more than 1000 times in the literature. The results of highly cited articles were compared against subsequent studies of comparable or larger, similar or better controlled, designs.The same analysis was also performed comparatively for matched studies that were not so highly cited.
The conclusions:
Contradiction and initially stronger effects are not usual in highly cited research of clinical interventions and their outcomes. The extent to which high citations may provoke contradictions and vice versa, needs more study. Controversies are most common with highly cited nonrandomized studies, but even the most highly cited randomized trials may be challenged and refuted over time, especially small ones.
To Sum up: Scientific research is the best tool we have for deepening and widening our knowledge of medicine and health care, but it is not perfect, and is subject to constant re-evaluation, revision, and change. What was taught in medical school 20, 10 or even 5 years ago, may be proven to be non-relevant and out-of-date data today.
The best course of action: stay attuned! Educate yourself! Check in periodically with the widely available libraries online and off it. Be discriminate in your choice of information sources. Check a few sources and compare.. We live in the age of information, it is easier than ever to access information about anything and everything, especially your own health! Take advantage! Empower yourself with the knowledge available to make your health and your life the best it can possibly be!
associated with such refutations over time.
The author examined all original research studies published in 3 major general clinical journals, or high-impact-factor
specialty journals in 1990-2003 and cited more than 1000 times in the literature. The results of highly cited articles were compared against subsequent studies of comparable or larger, similar or better controlled, designs.The same analysis was also performed comparatively for matched studies that were not so highly cited.
The conclusions:
Contradiction and initially stronger effects are not usual in highly cited research of clinical interventions and their outcomes. The extent to which high citations may provoke contradictions and vice versa, needs more study. Controversies are most common with highly cited nonrandomized studies, but even the most highly cited randomized trials may be challenged and refuted over time, especially small ones.
To Sum up: Scientific research is the best tool we have for deepening and widening our knowledge of medicine and health care, but it is not perfect, and is subject to constant re-evaluation, revision, and change. What was taught in medical school 20, 10 or even 5 years ago, may be proven to be non-relevant and out-of-date data today.
The best course of action: stay attuned! Educate yourself! Check in periodically with the widely available libraries online and off it. Be discriminate in your choice of information sources. Check a few sources and compare.. We live in the age of information, it is easier than ever to access information about anything and everything, especially your own health! Take advantage! Empower yourself with the knowledge available to make your health and your life the best it can possibly be!