Cherry Picking and Data Evaluation

Dear Julie,

Cherry picking is a term based on the perceived process of harvesting fruit, such as cherries. The picker would be expected to only select the ripest and healthiest fruits. An observer who only sees the selected fruit may thus wrongly conclude that most, or even all, of the tree’s fruit is in a likewise good condition. This can also give a false impression of the quality of the fruit (since it is only a sample and is not a representative sample).

Cherry picking occurs in science. Headlines in the news media, as well as even the most prestigious scientific journals, have been known to cherry pick data from research to support claims and attract attention. The news media grabs the attention of all of us by picking out sound bites from research that may not be representative of what the data actually shows. This suppression of evidence, or the fallacy of incomplete evidence, is the act of pointing to individual cases or data that seem to confirm a particular position while ignoring a significant portion of related cases or data that may contradict that position. It is a kind of fallacy of selective attention and may be committed intentionally or unintentionally.

We as clinicians have a responsibility to stay current in the latest research in our fields of speciality. Scientific studies are published. We examine the studies by reading the abstracts, and admittedly may often skip the methodology and go straight to the discussion and conclusion sections as our time is limited and dedicated primarily to patient care. When studies are published that contradict each other, then it makes it even more important for us to be able to critically evaluate the methods and data used by each team of researchers. So, how should clinicians—who are not experts in trial design or statistical analysis—interpret the results of research? Although the AREDs trial is considered a well-designed trial, the controversy regarding genetic testing and AMD with dueling statisticians is a good example of the difficulty we as clinicians can face in deciphering conflicting reports.

To help us critically evaluate scientific data published in journals and decipher whether this data is clinically relevant to we clinicians on the frontlines of clinical decision making, Dr. Stuart Richer has shared an article for this week’s Wellness Spotlight. In this article, Dr. Ronald Hoffman references a celebrated 2005 paper published titled “Why Most Published Research Findings Are False”. Among the assertions are “The greater the financial and other interests and prejudices in a scientific field, the less likely the research findings are to be true” and “The hotter a scientific field (with more scientific teams involved), the less likely the research findings are to be true.”

As a clinician with a speciality in nutrition, my patients are frequently asking me about news headlines concerning supplements or diets and disease. Will my fish oil give me prostate cancer? Is my vitamin E supplement bad for me? Have I been wasting my money buying fish oil to keep my heart healthy? Deciphering the research may take time, but it is our duty to the patients who have entrusted us with their care to give them the most accurate recommendations based on an appropriate interpretation of the data.