These are minimum statistical precision goals for each site. The expectation is that most sites would far exceed these targets. If your study design calls for a more stringent level of significance, you will require more samples . These results assume a coefficient of variation in trend of 1.0 among sites surveyed. Between-route variation has an inverse effect on power and if you think population trends vary more or less among your sites, you'll need to adjust your sample size.
Power is the ability of a monitoring program to detect a trend if one is really going on.
The reason lies in our goals. Page developed by Paige C. Eagle .