Adding noise (error) to biomass estimate used with the Broken Stick Management option
The broken stick case can be applied with perfect knowledge or with error (noise) added. There are three error options – set using estError (a vector with one entry per functional group): uniform (0), normal (1), lognormal (2). The specification of the error is set using estCV (the variance of the error as a proportion of the true value) and estBias (also as a proportion of the true value). Both of these parameters are entered as a vector, with one value per functional group.
Set Part II of the manual for the formulation of the error terms.
The parameters are put into the harvest.prm file and look like
error type applied (per species) to “perfect knowledge biomass estimate” for broken stick management (if not using formal assessment code)
uniform_err = 0
normal_err = 1
lognorm_err = 2
estError 53
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
error variance applied (per species) to “perfect knowledge biomass estimate” for broken stick management (if not using formal assessment code)
as proportion of the true value
estCV 53
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
bias applied (per species) to “perfect knowledge biomass estimate” for broken stick management (if not using formal assessment code)
as proportion of the true value
estBias 53
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0