7.2 Decision Mechanism
As in discrete sampling, there is no one decision mechanism dictated by the use of ISM sampling; a variety of decision mechanisms are possible. Each decision mechanism has strengths, weaknesses, and assumptions. In some cases, agency requirements will dictate the approach to be used. In other cases, a consensus on the decision mechanisms to be employed needs to be reached among members of the planning team prior to finalization of the sampling plan. Although decision mechanisms 1-3 are cast in terms of comparison with action levels, the same considerations apply when using ISM data to develop exposure point concentrations for baseline risk assessments.