Uncertainty

At first glance, confidence seems to be a reasonable measure of site assessment quality. If the confidence is high (and we are asking the right question), we can be assured of the reasonableness of the predicted values. You might be tempted to collect samples everywhere that the confidence was low, and if you did, your site would be well characterized.

But, there is a better, more cost-effective way. Instead of focusing on every place where confidence was low, we could focus on only those locations where there was low confidence and where the predicted concentration was reasonably high. We make that easy by providing the Uncertainty.

In EVS, uncertainty is high where concentrations are predicted to be relatively high (above the Clip Min), but the confidence in that prediction is low. If the goal is to find the contamination, using uncertainty allows for more rapid, cost effective site assessment. Uncertainty is the core of our DrillGuideTM technology which performs successive analyses using the location of Maximum Uncertainty to select new locations for sampling on each analysis iteration.

NOTICE: Uncertainty values should be considered unitless and their magnitudes cannot directly be used to assess the quality of a site assessment. Please observe the following precautions:

• Use Uncertainty as it was intended, as a guide to locations needing additional characterization.
• Do not use Uncertainty values directly to assess the quality of a site assessment
• A 50% reduction in Uncertainty magnitude cannot be construed as a 50% improvement in site assessment.

Our training videos cover the use of DrillGuide and how to properly use and interpret Uncertainty.