Thursday, December 5, 2013
1 reason I despise science headlines
For a week now, I've been pondering an article I came across in ScienceDaily - Dying from Food Allergy Less Likely Than Being Murdered. As all good headlines should do, they grab the reader's attention and make you want to read more... MORE! As a parent of a severely food allergic child, this headline certainly grabbed my attention and elicited a most visceral response - how dare they minimize our daily struggle and fear to prevent a life-threatening reaction (anaphylaxis) by comparing it to something completely unrelated (like murder?!)! After an eye roll so large that I thought my eyeballs would permanently cramp at the top of their sockets, I opted to let the emotion settle a bit and break this down further. Clearly, I'm biased, but I needed time to analyze this while recognizing my own biases to see if there is indeed merit to the article and the original peer-reviewed article it is based upon.
Does the ScienceDaily headline/article truthfully report the scientific findings?
Kind of. The title of the peer-reviewed article is certainly a bit less snazzy than the ScienceDaily version - Incidence of fatal food anaphylaxis in people with food allergy: a systematic review and meta-analysis (FYI - the article is freely available from the journal Clinical and Experimental Allergy). The entire point of this article was to systematically pool together data from multiple studies that reported death from food-related anaphylaxis over a certain time period (incidence) and essentially divide that by the number of individuals thought to have a food allergy (prevalence). There is even a lovely graph that shows the predicted range (which is large!) of the incidence of food allergy deaths compared to points of incidence for other causes of death in the general population (i.e. murder, accidental death, lightning, etc). Food allergic sufferers will be "happy" to know that according to this study, it is VERY ROUGHLY 10x more likely to die from anaphylaxis than a lightning strike. So the next time someone comes at you with lightning statistics, you can... strike that one down. Or can you?
Garbage in. Garbage out? As already mentioned, the error surrounding their predicted incidence of deaths due to anaphylaxis is quite large, so the true incidence is quite hard to pin down. The problem with their "input" is that there are known errors in coding the cause of death due to anaphylaxis (e.g. coded as asthma instead of the anaphylaxis that caused the response). Another "input" problem is the difficulty in nailing down the true prevalence of food allergy. The study authors are well aware of these issues, and in fact, attempt a sensitivity analysis to see how the incidence of food-related anaphylactic deaths changes with different food allergy prevalence values. The numbers reported in the ScienceDaily article are based on a conservative estimate of food allergy prevalence, 3% of the general population.
So does the ScienceDaily headline reflect reality? In my opinion, it was disingenuous to compare the very squishy statistic of food-allergy related deaths to murder deaths. The predicted incidence values for food-related allergy deaths and murder are not nearly far enough away from one another for any comfort in that conclusion (in fact, no error values are reported for any of the "other" causes of death). Isn't it just apples and oranges anyway? The study authors themselves stick with a much more reasonable conclusion based on a more probable true difference in incidence and not so much emotion that "fatal food anaphylaxis for a food-allergic person is rarer than accidental death in the general population." Why didn't ScienceDaily report that? My conclusion is that the knee-jerk response of being compared to "murder" is a much more effective headline. So, yes, this is "1 reason I despise science headlines." I'll point out that unfair statistical comparisons is one of many reasons to loathe science headlines. Unfortunately, I'm sure there will be more fodder for future blog posts.
Stay tuned for a follow-up post (Link to follow-up post). I will put these findings in the context of what it means for the food allergic individual (or their caregivers) and highlight the recent study in the Journal of Allergy and Clinical Immunology (JACI), Anaphylaxis in America: The prevalence and characteristics of anaphylaxis in the United States.
PS - In an attempt to understand how headlines are written, I did a cursory Google search for "writing great headlines." My blog title reflects that advice - complete with a numerical value as the lead. We'll see how many blog hits I get (so scientific and completely unbiased, right?)!