I hinted at it in the last post, and some readers also made similar suggestions. What happens if we plot the U.S. life expectancy data in relative terms (indiced) rather than in absolute terms?
The result is highly revealing, and that is why we should always look at the data many ways. While in the original chart, the differences in the race/gender segments were essentially obscured by the overall slowly-growing trend, in our new chart, we took out the trend, isolating the growth rates.
The reconstructed chart showed that:
- Between 1970 and roughly 1990, blacks of both genders gained in life expectancy at a rate higher than the national average, while white females lagged behind white males
- However, almost all of the gain by blacks were attained between 1970 and 1984, and in the 10-15 years following, this excess gain was wiped out so that by 1992 or so, the black male, black female and white male lines again converged.
- Starting in 1995, black males again achieved significant improvement in life expectancy. This time, black females did not follow their male counterparts. Meanwhile, white females continue to lag behind.
Reference: "CDC says life expectancy in the US is up, deaths not", Miami Herald, Aug 19 2009. CDC Life expectancy data.