LIFE TABLES AND SUVIVORSHIP CURVES

 Running Head: LIFE TABLES AND SUVIVORSHIP CURVES 1
Essay
Name:
Institution:
Instructor:
Course:
Date of Submission:
LIFE TABLES AND SUVIVORSHIP CURVES 2
How do the data from the cemetery compare to that from the newspaper? If they do not
differ, suggest why. Do the two populations differ in survivorship? At what ages, do they
differ? What possible factors may account for these differences?
Using the survivorship curve and qx, which is the probability of someone dying before
age x+1, to measure longevity, it is evident that there is stark contrast between cemetery data,
which represent pre-1990, and post-1990, which represent post-1990. Survivorship rate is higher
during post-1990 than during pre-1990. During pre-1990, rapid decline in the number of people
alive is at the ages of 60-69 while during post-1990, it is at the ages of 70-79. During the post1990, there is a possibility of a person attaining more than 100 years whereas during the pre1990 the terminal age a person of either sexes can attain is between the ages of 90 to 99. This
observation is reaffirmed by comparing qx of both time periods and for both sexes. qx for pre1999 is higher than qx for post-1990, showing that people were at greater risk of dying during
pre-1990 than in post-1990. There are differences in survivorship between sexes in the two time
periods, pre-1990 and post-1990. During pre-1990, males have higher survivorship rate than
females while in post-1990, females have higher survivorship rate than males.
Differences in survivorship rates in both time periods may be attributed to several factors.
One is improved healthcare services during post-1990, thus contributing to reduced mortality
cases. Unlike pre-1990 when people died from preventable disease. Secondly, higher income
afford people to eat healthy foods that contribute to overall improved health, consequently,
reducing cases of nutritional diseases and deaths (Francis, 2012).
How do the sexes differ in survivorship and longevity? Is the pattern different now
compared with pre-1900? At what ages, specifically, have the greatest changes in mortality
occurred? Can you think of reasons for these changes?
Survivorship will be assessed using the survivorship curve while longevity will be
accessed using Lx. Comparing the survivorship and longevity of sexes in respective period that is
pre-1900 and post-2000 indicate slight differences between the two sexes. During the pre-1900, 
LIFE TABLES AND SUVIVORSHIP CURVES 3
males show a slightly higher survivorship rate as compared to women. However, both sexes
show rapid decline in the number of people alive at the ages of 60-69. Longevity will be
assessed using Lx , which is the number of person-years lived in age (x, x+n) (Swanson, Siegel &
Shryock, 2004). It is evident from the life table that Lx for males is higher than of females upto
the ages of 70-79; however, after the ages70-79 females show higher Lx. This is interpreted to
mean that males recorded higher longevity than females during pre-1990 up to the ages of 70-79,
and thereafter from 70-79 females’ longevity increases than that of males. This supposition is
confirmed by lx, which shows that more females attain the age of 90-99 than males.
Comparing the survivorship and longevity of sexes in post-1900, it is evident from the
survivorship curve that females have higher survivor rates than males. Similarly, evaluation of
longevity illustrates the same case. Lx, shows that the number of person years lived in age
interval (x, x+n) is higher for females than for males; however, males are at a higher probability
of attaining ages greater than 100. This illustrates that during post-1990 females record higher
longevity than males. Both sexes show rapid decline in the number of people alive at the ages of
70-79, with that of male been sharper than for females. Surprisingly, all females die at the ages
of 90-99, but males have a probability of attaining more than 100 years. The greatest change in
mortality for pre-1990 occurred at the ages of 60-69 while for post 1990 is at ages of 70-79. This
is because of senility, as it results to people growing weak and eventually dying.
What two possible biases might there be in you method of data collection? (Are babies as
likely to be reported in the newspaper as adults? How might demographic changes over the
last 100 years bias the cemetery data? what about age-specific immigration rates?
During data collection a number of biases may arise: a) Overestimation or
underestimation of births. b) Overestimation or underestimation of deaths c) overestimation or
underestimation of population. Inaccurate data on births, deaths and population results to biased
life table, consequently, inaccurate results. For example, it is easier to ascertain data of births that 
LIFE TABLES AND SUVIVORSHIP CURVES 4
is babies born in post-1990 than in pre-1990 because mothers are giving birth in hospitals in
develo