This is an old revision of the document!
The purpose of this section is to compare the estimates from our model, with those of the ICES VPA models.
VPA trajectories and confidence intervals for the estimated population trajectories
One feature of ADMB is that it can produce standard deviations of dependent variables as well as independent variables, so that the user does not need to employ the delta method or similar techniques. In this section we plot the corresponding confidence intervals for the models given in the section on real data.
In addition, each plot includes the corresponding VPA estimates for each population, for comparison.
Choosing which cohorts to estimate
We assume that from a numerical point of view, it is beneficial to estimate cohorts of large size. To get an idea of which cohorts are the largest we plot the survey indices, given below:
 |  |  |  |
As can be seen, the cohorts born in 1994 to 1997 seem to be the strongest. Also, the curves are not monotoic, with the curve for the cohort born 1988 having a particularly challenging shape. This should be taken into consideration when designing the model.