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There is an issue accommodating short time blocks at the end of the model time series in a retrospective. Specifically it isn't possible to estimate parameters when time blocks are peeled back to < 3 years.
During a meeting 5/21/19, @scdressel and I discussed 4 alternatives to address this issue. To illustrate the problem and alternatives, I will use the example of natural mortality (M) time blocks from 1980-1998, 1999-2014, and 2015-2017.
Alternative 1: Remove the last time block and run the retrospective with only 2 time blocks. E.g. Assume time blocks for M are 1980-1998 and 1999-2017.
Not preferred because this is a different model. It is the easiest to code.
Alternative 2: For retrospective peels that results in time blocks <= 2 yrs, fix the parameter to the estimate obtained with 3 yrs.
Not preferred because it could mask poor retrospective behavior. Also challenging to program.
Alternative 3: For retrospective peels that results in time blocks <= 2 yrs, remove time block. So for peel 0, the time blocks are 1980-1998, 1999-2014, and 2015-2017, for peel 1 they are 1980-1998 and 1999-2016, and for peel 2 they are 1980-1998 and 1999-2015.
Preferred alternative. It is a compromise between Alternatives 1 and 4 that closely matches how time blocks are added to the model (they have to be at least 3 yrs in length before being considered).
Alternative 4: If the peels don't run, do not report them in the figures or include them in the calculation of Mohn's rho.
Second preferred alternative. Concern that we lose this information completely.
The text was updated successfully, but these errors were encountered:
…time block.
- Fixed retrospective figure and applied rule to remove time block if <= 2 years. #4
- Major folder rorganization and code review. All analyses in 2018_forecast reviewed and revised to run in new structure. All figs now in results folder.
There is an issue accommodating short time blocks at the end of the model time series in a retrospective. Specifically it isn't possible to estimate parameters when time blocks are peeled back to < 3 years.
During a meeting 5/21/19, @scdressel and I discussed 4 alternatives to address this issue. To illustrate the problem and alternatives, I will use the example of natural mortality (M) time blocks from 1980-1998, 1999-2014, and 2015-2017.
Alternative 1: Remove the last time block and run the retrospective with only 2 time blocks. E.g. Assume time blocks for M are 1980-1998 and 1999-2017.
Alternative 2: For retrospective peels that results in time blocks <= 2 yrs, fix the parameter to the estimate obtained with 3 yrs.
Alternative 3: For retrospective peels that results in time blocks <= 2 yrs, remove time block. So for peel 0, the time blocks are 1980-1998, 1999-2014, and 2015-2017, for peel 1 they are 1980-1998 and 1999-2016, and for peel 2 they are 1980-1998 and 1999-2015.
Alternative 4: If the peels don't run, do not report them in the figures or include them in the calculation of Mohn's rho.
The text was updated successfully, but these errors were encountered: