A Power Analysis Tool for Habitat Condition Monitoring

The Countryside Council for Wales (CCW) and Natural England (NE) both required power analyses to indicate sample sizes required for habitat condition assessments. Rather than undertake "one-off" analyses of a limited number of strategies, BioEcoSS Ltd. created an interactive Power Analysis Tool that allowed users to set up to ten parameters to see their effect on power and significance. This allowed users to carry out "what if" type analyses to focus their power analyses on realistic and useful scenarios

a) The interactive Power Tool was built as a stand-alone MS Access application which used a sophisticated set of simulation algorithms to undertake power analysis in real-time. It included ten parameters (population, sample and analysis parameters) which allowed, literally, millions of combinations of user-definable values. The Power Tool provided two types of output; three-dimensional graphs of theoretical power analyses and tabular output of empirical data derived from previous studies.
b) To accompany the Power Tool, BioEcoSS Ltd. produced a comprehensive user guide and report. This report made use of the outputs from the tool to explore the effects of a number of parameters, such as sample size, population size, intrinsic rates of change and initial starting conditions on the power to detect change. This was expanded with an exploration of the practical sample sizes required, given known parameter values from pilot studies.