Life expectancy?

Earlier this week, I noticed Tweets from people alarmed about a shockingly low life expectancy of only 37 years for aboriginals in Toronto.  This instantly seemed wrong.  The links lead to an article on the Kevin Newman Live website by a producer, Jordan Chittley.  I found the number cited to be unbelievable and it is.  Colby Cosh caught the error but many others did not.  I sent a series of tweets to the author; the headline and article have since been edited but still contain errors.

The story reports the results of a study “Early deaths among members of Toronto’s aboriginal community” written by three doctors — C.P. Shah, R. Klair, and A. Reeves — from Anishnawbe Health Toronto.  The data used for the study was from just 109 deaths of patients from four clinics in Toronto over three years.

The original article and headline referred to “life expectancy” which is quite different from “average age at death”.  Calculating life expectancy requires knowing the risk of death at each age (or in each age group) in a population.

The authors of the report did not even actually calculate average age at death for aboriginals in Toronto.  They only calculated the average age at death for patients in their clinics who died during those three years.  This doesn’t account for all of the patients who haven’t died yet or all of the aboriginals who are not patients at their clinics.  Their data is useless.  They might be able to make a comparison if they could identify non-Aboriginal patients at similar clinics but even then they are just comparing people who died.  What percent of patients died?  What were the causes of death?  Who is their patient population?  Is it representative of the entire aboriginal population of Toronto?  So many unanswered questions.

The errors in the report are perpetuated by the media including the corrected version of the CTV article.  Almost every article that I’ve seen compares the average age of death of this small group (37 years) to the correctly calculated life expectancy of Toronto residents (75 years).  The two statistics are completely different and should never be compared.  At least Metro News got it right. 

So what are the facts?  Aboriginals do have a lower life expectancy than non-Aboriginals but only by a few years and both groups can expect to live far past 37 years.



Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s