The main reason epidemiology is hard... urgency

There's a point I should have emphasized in my previous post about this news story

Researchers have long documented that the most educated Americans were making the biggest gains in life expectancy, but now they say mortality data show that life spans for some of the least educated Americans are actually contracting. Four studies in recent years identified modest declines, but a new one that looks separately at Americans lacking a high school diploma found disturbingly sharp drops in life expectancy for whites in this group. Experts not involved in the new research said its findings were persuasive.

I commented that cohort effects could complicate things in a study like this. What I should have made clear was that, even with these complications:

1.  These numbers are horrifying;

2. Even if the effects are less dramatic than what the most recent study indicated, there is considerable evidence that life expectancies are getting worse for the most disadvantaged people in our country.

I'm primarily a marketing statistician. I hardly ever make life and death decisions. Epidemiologists play for higher stakes. I believe it's healthy for outside statisticians like me to point out concerns with epidemiological research, but we need to remember that researchers inside the field don't have the option of waiting for a perfect data set. Their findings have a huge impact on the health of millions of people and those millions can't wait for perfect.