Thursday, November 02, 2006

Mortality rates

I was thinking about the "mortality rate" statistic that was used by Johns Hopkins Bloomberg School of Public Health for their examination of Iraqi death rates. The mortality rate is simply the number of deaths per thousand people in a given society.

Perhaps the most curious aspect of the Johns Hopkins study is that the pre-war mortality rate in Iraq was 5.5 deaths per thousand, which is also the CIA's pre-war estimate. What makes that estimate so hard to grasp is that before the war we heard so much about how Iraq's civilian population was suffering thanks to the sanctions regime. Yet, a death rate of 5.5/1000 is significantly lower than the mortality rates of the United States (8/1000), Ireland (8/1000), the UK (10/1000), or Germany (10/1000). It seems odd that Iraq's death rate would be so much lower than that which prevails in W. Europe or the US, but the population structure has a big effect on mortality rates and 'the west' is a lot older than Iraq (and the rest of the Middle East).

Anyway, the Hopkins information is based on Iraqi government statistics, which are also the source of the CIA's numbers. However, the current Iraqi government statistics (& CIA) figures estimate the death rate in Iraq at around 5.4/1000, while the Hopkins study puts the rate at 13.3/1000. Obviously, one of them must be wrong.

Another curiosity is that the Hopkins study "recorded 1,474 births and 629 deaths among 12,801 people surveyed". That gives a ratio of 2.34 births for every death. The CIA ratio for 2006 is just 5.995 births for every death (the CIA's estimate for the ratio in 2000 was 5.475). Another substantial discrepancy.

By the way, South Africa's mortality rate is 22/1000 (same as in 2000), which is far worse than the Hopkins estimate for Iraq.