Lab #5: Direct and Indirect Standardization of Mortality Rates

We have been discussing mortality as it has changed over time in developed and
developing regions. Even within the same country, mortality can change due to differences
in environmental or cultural factors. Also, a population’s age and gender composition
can cause variations in mortality rates. Geographers interested in mortality or disease
often want to be able to compare rates in two locations or at two scales in order to
identify whether there are spatial factors such as the local natural or built environment
or cultural factors that influence a rate. In order to make such a comparison, one needs
to adjust for differences in age composition. Since the highest age-specific mortality
rates occur at the youngest and oldest age cohorts, populations with large child and
elderly populations will have higher mortality rates. In order to eliminate the influence
of age composition, one can compute a * standardized death rate*.

A * standardized death rate *is a crude death rate that has been adjusted
for differences in age composition between the region under study and a

There are two ways of computing standardized death rates – direct and indirect standardization. The results will be a little bit different. The one you would use varies based on the data available to you.

__ Direct Standardization__ (SDR

__ Indirect Standardization__ (SDR

Direct Standardization:

**SDR _{1}** = [Sum

M_{ar} is the age-specific mortality rate for the region.

P_{as} is the number of people in the age group in the standard population.

P_{s} is the total standard population.

To compute the direct standardized mortality rate:

1. For each age group, you need to multiply M_{ar} by P_{as}.

2. Add them up.

3. Divide the sum by the total standard population.

4. Multiply by 1000, or give the rate in terms of "per thousand population."

Indirect Standardization:

**SDR _{2} **= D

M_{as} is the age-specific mortality rate for the standard population.

P_{ar} is the number of people in the age group in the region’s population.

D_{r} is the number of deaths in the region.

CDR_{s} is the crude death rate for the standard population.

To compute the indirect standardized mortality rate:

1. For each age group, you need to multiply M_{as} by P_{ar}.

2. Add them up.

3. Divide the sum into the number of deaths in the region.

4. Multiply by the crude death rate.

Choosing which formula to use will depend on what data you have access to. More
typically, the data you have will be the components for indirect standardization. You are
more likely to be able to find age-specific mortality rates for a standard population than
for a specific region such as a state. *In this case, since I have given
you state population data in thousands, you will need to divide your final
result by 1,000.*

For this lab, you will be computing standardized death rates of New York and Arizona using the following data sets and the US as the standard population.

The fastest way to compute the direct and indirect rates will be to enter the measures
you need into Excel, remembering to compute formulas from the inside out. See if you can
figure out how to enter this into Excel. (These tables are taken from D. Plane and P.
Rogerson. 1994. * The Geographic Analysis of Population with Applications to Planning
and Business.* New York: John Wiley & Sons, Inc.) Be careful! Think
about what data you need and whether you need all the data I have given you! You
will need to type these into Excel. These tables will not directly import into
Excel.

Table 1. US Population in thousands and State Age-Specific Mortality Rates | |||||||

Age | Population | New York | Arizona | ||||

0-4 | 18,456 | 0.00272 | 0.00269 | ||||

5-24 | 72,053 | 0.00066 | 0.00076 | ||||

25-34 | 43,675 | 0.00192 | 0.00146 | ||||

35-44 | 35,264 | 0.00321 | 0.00224 | ||||

45-54 | 24,163 | 0.0054 | 0.00484 | ||||

55-64 | 21,830 | 0.01212 | 0.01102 | ||||

65-74 | 17,897 | 0.02793 | 0.02408 | ||||

75+ | 12,470 | 0.08753 | 0.07359 | ||||

Source: U.S. Bureau of the Census, 1990; U.S. Dept. of Health and Human Services, 1989.

Table 2. U.S. Age-Specific Mortality and State Populations in Thousands | ||||||

Age | US Death | New York | Arizona | |||

Rate | Population | Population | ||||

0-4 | 0.00251 | 1,275 | 299 | |||

5-24 | 0.00065 | 5,023 | 1,028 | |||

25-34 | 0.00135 | 3,018 | 614 | |||

35-44 | 0.0022 | 2,572 | 479 | |||

45-54 | 0.00486 | 1,909 | 315 | |||

55-64 | 0.01236 | 1,784 | 307 | |||

65-74 | 0.0273 | 1,347 | 277 | |||

75+ | 0.08513 | 981 | 170 |

Source: US Bureau of the Census (1989). US Dept. of Health and Human Services (1990).

Total deaths in New York: 176,289 |

Total deaths in Arizona: 27,646 |

US Crude Death Rate: 8.818 |

In this lab, you will be selecting the right data from these tables in order to compute a direct and an indirect standardization of the death rate of these two states.

SDR_{1 }for New York =

SDR_{2 }for New York =

SDR_{1 }for Arizona =

SDR_{2 }for Arizona =