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TrendPowerTool: A web lookup tool for estimating the statistical power of a monitoring program to detect population trends Active

By Upper Midwest Environmental Sciences Center January 12, 2021

A simulation-based power analysis can be used to estimate the sample sizes needed for a successful monitoring program, but requires technical expertise and sometimes extensive computing resources. We developed a web-based lookup app, called TrendPowerTool, to provide guidance for ecological monitoring programs when resources are not available for a simulation-based power analysis (Fig. 1). TrendPowerTool is implemented through the shiny package in R, but is accessible through a webpage without the need for users to install any added software. By drawing on results of 1.4 million scenarios that we simulated on a supercomputer, TrendPowerTool quickly and easily provides estimates of the statistical power to detect a population trend of a particular magnitude for a planned monitoring program (e.g., Fig. 2), based on user-specified parameters for the monitoring design and population of interest. TrendPowerTool provides a user-friendly interface that retrieves results instantaneously, facilitating the important step of conducting a power analysis when designing monitoring programs.

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Plot depicting power to detect a trend of -4% per year over 5 years at various sample sizes.
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Figure 1. Plot depicting power to detect a trend of -4% per year over 5 years at various sample sizes.

 

Figure 2. Estimates of statistical power at varying levels of trend made possible by TrendPowerTool for four example datasets
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Figure 2. Estimates of statistical power at varying levels of trend made possible by TrendPowerTool for four example datasets (see Weiser et al. 20xx for further details).