From the Archives: Understanding Risk: Tricky Business 3

Note to readers: The attached article (click on the image to download the PDF) about understanding risk was originally published in the Harvard Health Letter in 1994. I recently stumbled across it in my archives and thought some readers here might enjoy it. Although it is directed at a consumer and not a professional audience, I think it’s very important for all of us to consider how we think about risk and communicate our understanding to others.

Sometimes our lack of progress can be disheartening, as evidenced by the brief mention in the story of cell phones and brain cancer. The one obvious mistake in the piece is the paragraph on estrogen. The general concept is still correct, but clearly the benefits of estrogen did not turn out as we thought back in the nineties. In a way, though, this illustrates the larger point of the piece, which is that understanding risk is a tricky business.

Click to view the entire article.



  1. Thanks, Franz. Two roads diverged… Generally I’ve found it easier to stay employed writing for professionals than for the general public. FYI, I’ve recently started thinking about getting back into the consumer sphere. Perhaps I’ll have something to report on that next year.

  2. this information is as valid now as it was 1n 1994. writing for a lay audience can be more difficult than preaching to the choir. just this year i wrote the following addressed to patients about risk assessment for cardiac surgery —
    When surgeons explain the risks and benefits of a particular operation they present to patients and their families a lot of “numbers”. Statistical analysis is the way these numbers are “crunched” that leads to the decision that cardiac surgery is the best option. It is most easily understood as the method of predicting the odds that an event will occur. For example, let us say a patient is told there is a 2% chance of developing a wound infection after surgery. That chance has been calculated by the fact that of the last 100 patients operated upon 2 developed wound infections. Therefore, the likelihood of this event occurring is very low, but that does not guarantee a specific patient that his or her wound will not become infected. Second, statistical analysis can compare the frequency of an event happening between groups of patients and determine whether that difference is real or just due to chance. Is there a difference between the operative mortality at two hospitals or does one therapy improve survival as opposed to another? Again, this does not guarantee for a specific patient the better outcome, it means the odds are better with one choice versus another. Your chances of winning when betting on the Kentucky Derby are better if you bet on the favorite, but the favorite does not always win. And finally, statistics allow you to compare apples to apples, not apples to oranges. The operative outcomes at two hospitals may be different, but one hospital has older, sicker patients whose expected risk would be higher. Statistics can take account of these differences to allow more valid comparison.
    This information is provided not to suggest that patients buy a statistics textbook before signing the consent form , but to prepare everyone for the unavoidable uncertainty surrounding all aspects of cardiac surgery. Open heart surgery is a scary prospect and the natural reaction is to ask for guarantees. Surgeons are pushed for reassurance that everything will be alright, and this is understandable. The most common question asked is when can we stop worrying. The care givers at all levels want to give reassurance, but be forewarned, a confident we believe he is doing fine or we have every reason to suspect she will make a full and uneventful recovery is the most responsible answer.

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