Statistical AnalysisWe compared the

Statistical Analysis
We compared the overall and cause-specific mortality
rate (number of deaths per 1000 live
births) and the proportionate mortality (relative
percentage contribution) for the coded causes of
death among infants born in three birth-year
periods: 2000–2003, 2004–2007, and 2008–2011.
We selected comparisons among three birth-year
periods instead of individual birth years to provide
a sufficiently large sample to control for
confounding in our analysis and to provide mortality
estimates with greater precision.