Fenelon and Preston discuss how smoking cigarettes has caused a great deal of premature deaths in the United States. The objective of the authors was to provide more accurate estimates of how smoking effects life expectancy of adults in the United States for the year 2004. They utilized the Preston/Glei/Wilmoth (PGW) model to estimate coefficients derived from the data obtained from the National Center for Health Statistics (NCHS). They found that 60% of mortality in southern states could be attributed to smoking when compared to other regions of the country. Based on the various results obtained from this study the data matched that of the Centers for Disease Control and Prevention (CDC), however they observed that mortality rates differed by state in comparison to what the CDC observed.