SimSurvey: An R package for comparing the design and analysis of surveys by simulating spatially-correlated populations

Abstract

Populations often show complex spatial and temporal dynamics, creating challenges in designing and implementing effective surveys. Inappropriate sampling designs can potentially lead to both under-sampling (reducing precision) and over-sampling (through the extensive and potentially expensive sampling of correlated metrics). These issues can be difficult to identify and avoid in sample surveys of fish populations as they tend to be costly and comprised of multiple levels of sampling. Population estimates are therefore affected by each level of sampling as well as the pathway taken to analyze such data. Though simulations are a useful tool for exploring the efficacy of specific sampling strategies and statistical methods, there are a limited number of tools that facilitate the simulation testing of a range of sampling and analytical pathways for multi-stage survey data. Here we introduce the R package SimSurvey, which has been designed to simplify the process of simulating surveys of age-structured and spatially-distributed populations. The package allows the user to simulate age-structured populations that vary in space and time and explore the efficacy of a range of built-in or user-defined sampling protocols to reproduce the population parameters of the known population. SimSurvey also includes a function for estimating the stratified mean and variance of the population from the simulated survey data. We demonstrate the use of this package using a case study and show that it can reveal unexpected sources of bias and be used to explore design-based solutions to such problems. In summary, Sim-Survey can serve as a convenient, accessible and flexible platform for simulating a wide range of sampling strategies for fish stocks and other populations that show complex structuring. Various statistical approaches can then be applied to the results to test the efficacy of different analytical approaches.

Science Priorities for Offshore Wind and Fisheries Research in the Northeast U.S. Continental Shelf Ecosystem: Perspectives from Scientists at the National Marine Fisheries Service

“…The effects of changing survey approaches on the provisioning of scientific advice can be examined using observation system simulation models (Regular et al. 2020). Research into new methods that can augment existing surveys is also needed.…”

“…Advancing research methods and scientific practices for evaluating existing scientific survey designs and the identification, evaluation, and integration of new survey approaches are primary steps (Gill et al 2020;Methratta et al 2020). The effects of changing survey approaches on the provisioning of scientific advice can be examined using observation system simulation models (Regular et al 2020). Research into new methods that can augment existing surveys is also needed.…”

Re: Implications for the future of Obstetrics and Gynaecology following the COVID‐19 pandemic: a commentary

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“…We believe that a specific protocol for choosing the sample facility can eliminate the possibility of selection bias. 2 Also, maintenance of the cold chain is integral for the potency of oxytocin, it would be of importance to mention if this facet was adhered to strictly because Uttar Pradesh is known for its frequent episodes of power cuts. Furthermore, it would be helpful if the authors could share the '28 essential birth practices' checklist, to allow better understanding of the coaching involved in training the birth attendants.…”