Calculates how the sample size decreases in time due to population mortality
Usage
nessie(
formula = formula(data),
data = parent.frame(),
ratetable = relsurv::slopop,
times,
rmap
)
Value
A list of values.
Arguments
formula
a formula object, same as in rs.surv. The right-hand
side of the formula object includes the variable that defines the subgroups
(a variable of type factor) by which the expected sample size is to
be calculated.
data
a data.frame in which to interpret the variables named in the
formula.
ratetable
a table of event rates, organized as a ratetable
object, such as slopop.
times
Times at which the calculation should be evaluated - in years!
rmap
an optional list to be used if the variables are not organized
and named in the same way as in the ratetable object. See details of
the rs.surv function.
Details
The function calculates the sample size we can expect at a certain time
point if the patients die only due to population causes (population survival
* initial sample size in a certain category), i.e. the number of individuals
that remains at risk at given timepoints after the individuals who die due
to population causes are removed. The result should be used as a guideline
for the sensible length of follow-up interval when calculating the net
survival.
The first column of the output reports the number of individuals at time 0.
The last column of the output reports the conditional expected (population)
survival time for each subgroup.
References
Pohar Perme, M., Pavlic, K. (2018) "Nonparametric Relative
Survival Analysis with the R Package relsurv". Journal of Statistical
Software. 87(8), 1-27, doi: "10.18637/jss.v087.i08"