Does it make a difference which estimates are used to calculate disease rates?
• All data concerning the size of the population are subject to error. The farther removed the estimates are from the 100% count of the population, the larger the degree of error will be. This means that estimates for 1991 are probably more accurate than estimates for 1997. In addition, estimates concerning smaller populations will be affected by error much more than estimates of large populations. This compounds the instability of incidence and mortality rates for smaller populations, which also have fewer incidence cases and deaths to base the rates on. • “Error of closure” is the difference between the estimated population at the end of a decade and the census count for that date. The error of closure at the national level was quite small during the 1960’s (379,000 persons). The error of closure for the 1970’s, however, amounted to almost 5 million persons. For the 1980’s, it was 1.5 million persons. • Small differences between the population estimates usually would not create meani
