Indexing the Expected Probabilities for Each Individual Patient

Let:

r = race of individual

s = sex of individual

g = age at entry into life table

y = calendar year of entry into life table

x = interval of follow up

Index for Expected Probabilities

Annual Interval	Race	Sex	Age	Age Date
1	r	s	g	y
2	r	s	g+1	y+1
3	r	s	g+2	y+2
...	...	...	...	...
x	r	s	g+(x-1)	y+(x-1)

For non-annual intervals, the expected survival table is expanded from years to months by taking the twelfth root of the yearly survival. For example, if the annual (January to December) expected survival for white males age 6 in 1970 is 0.99957, then 0.99996 would be the survival for each month of 1970.