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Methods Working Group (MGWG; outputs from 2024 meeting)

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posted on 2025-01-21, 14:11 authored by ICESICES

The objective of the Methods Working Group (MGWG) is to improve existing assessment models and develop new ones, organize a collection of datasets, test the performance of new and existing models, and work on assessment related techniques. The MGWG provides expertise to examine the inner workings of models and methods.

The group has focused on evaluating, validating, and sharing new techniques from stock assessment models and methods, as well as providing a reference document of model diagnostics to guide expert group meetings. Additionally, the MGWG communicates with ICES about training course needs and addresses questions supplied by expert groups. The MGWG meeting provides opportunities to advance these terms of reference (ToRs) and common themes have been the proper characterisation of the statistical features of output and advances in software such as RTMB (Template Model Builder), machine learning approaches, and recent developments in the general assessment tools FIMS (Fisheries Integrated Modelling System), SAM (State-space Assessment Model), a4a, smsR, and bespoke models. Case studies explored issues ranging from data limitations to spatial complexity to genetic pedigrees to management issues. A number of simulation studies using state-space models demonstrated the importance of continued simulation testing of all approaches used in stock assessment. The main highlights include a new method to estimate the uncertainty of Mohn’s rho, a measure of the retrospective pattern in a stock assessment, the new development of RTMB, and a novel method to solve a problem of 'spikes' in the likelihoods, which are artificially introduced by the Laplace approximation. MGWG produced a first version of a reference document describing a wide range of stock assessment model diagnostics that should routinely be reported at benchmarks meetings and a subset to be reported at assessment working groups.

History

Published under the auspices of the following ICES Steering Group or Committee

  • HAPISG

Published under the auspices of the following ICES Expert Group or Strategic Initiative

MGWG

Series

ICES Scientific Reports

Volume

7

Issue

12

Contributors (Editors)

Andrea Havron; Anders Nielsen

Contributors (Authors)

Anders Nielsen; Andrea Havron; Casper Berg; Charles Perretti; Chengxue Li; Chris Cahill; Chris Legault; Christine Stawitz; Christoffer Moesgaard Albertsen; Colin Millar; Daniel Howell; Daniel Ruzzante; Ellie Weise; Emily Liljestrand; Jonathan Babyn; Jonathan Deroba; Kasper Kristensen; Lisa Chong; Liz Brooks; Maria Soto; Matthew Supernaw; Mollie Brooks; Nicola Walker; Nis Jacobsen; Noel Cadigan; Olav Breivik; Tobias Mildenberger

ISSN

2618-1371

Recommended citation

ICES. 2025. Methods Working Group (MGWG; outputs from 2024 meeting). ICES Scientific Reports. 7:12. 101 pp. https://doi.org/10.17895/ices.pub.28247921

Publication language

  • en

File format(s)

  • PDF

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