inversely related to the variances of the estimates. The algorithm uses the Fisher’s
scoring method and the Newton-Raphson method reduce to the same algorithm.
The expected death rate may be written as follows:
λxtc / Lxtc =καxβtτc expγZxtc
where the parameters are restricted as follows: α1=1, βt=1 and τc = 1 and κ is an overall
scale parameter. Alternative restrictions may be used.
(7)