Since the process is markovian, one can write:
This leads to:
involving elementary stochastic matrices
which can be directly deduced from observed data. The LSOA survey uses
basic matrices 
instead of 
,
therefore each 
matrix can be directly computed by simple
products of matrix
.
Most important outputs concern life expectancies which are expressed
in 
as integer on time
of a function 
giving the
status at time t. But this function is known for
each two year period, so life expectancies can be computed directly from the
data without having to estimate forces.