Question

Calculate and Interpret Adjusted/Standardized and Unadjusted Mortality Rates

Using these data, calculate and record your answers in the blanks below. This exercise is meant to illustrate the effect of age composition on Crude Death Rates (CDR).

	FAMILY LAND Suburban Population			SUN CITY Retirement Community
	Mid year population	Death Rate (per person)		Mid Year Population	Death Rate (per person)
0-14	1125	0.025		1132	0.025
15-29	2342	0.013		875	0.013
30-49	1508	0.026		1736	0.026
50+	503	0.110		3458	0.110

                                                                                    Family Land                Sun City

            Total Population Size                                     __________                ___________

            Number of deaths to persons 0-14                 __________                ___________

            Number of deaths to persons 15-29               __________                ___________

            Number of deaths to persons 30-49               __________                ___________

            Number of deaths to persons 50+                  __________                ___________

            Total Number of Deaths                                 __________                ___________

            Crude Death Rate (CDR), per 1000               __________                ___________

            Percentage of total population age 50+         __________                ___________

These two populations have the exact same age-specific death rates. Why do their CDRs differ so dramatically?

Answer 1

FAMILY LAND				SUN CITY
									Mid year population	Death Rate		Mid Year Population		Death Rate	Number of deaths
(per person)	Number of deaths	(per person)
0-14	1125	0.025	28.125	1132		0.025	28.3
15-29	2342	0.013	30.446	875		0.013	11.375
30-49	1508	0.026	39.208	1736		0.026	45.136
50+	503	0.11	55.33	3458		0.11	380.38
Total	5478		153.109	7201			465.191

	Family Land	Sun City
Total Population Size	5478	7201
Number of deaths to persons 0-14	1125*0.025=28.125 =28	1132*0.025=28.3 = 28
Number of deaths to persons 15-29	2342*0.013=30.446 =30	875*0.013=11.375 =11
Number of deaths to persons 30-49	1508*0.026=39.208 =39	1736*0.026=45.136 =45
Number of deaths to persons 50+	503*0.11=55.33 =55	3458*0.11=380.38 = 380
Total Number of Deaths	153.109 =153	465.191 =465
Crude Death Rate (CDR), per 1000	153/5478 = 0.0279	465/7201 = 0.0646
Percentage of total population age 50+	(503/5478)*100 = 9.18%	(3458/7201)*100 =48.02%

CRUDE DEATH RATE (CDR) is the total number of deaths to residents in a specified geographic area (country, state, county, etc.) divided by the total population for the same geographic area (for a specified time period, usually a calendar year) and multiplied by 100,000.

i.e., CDR = total resident deaths / total population

The above two populations have the exact same age-specific death rates but different mid year population.

So, the CDR differ dramatically.