Table 3.

A proposal for unified efficiency criteria to be used in the cost-efficiency assessments of novel monitoring methods

Efficiency factor	Definition
Type I: Number of samples needed	Aim: keeping the representativeness at an acceptable level compared to the present method Required analysis: the minimum amount of samples/data based on documented sources
Type II: The number of indicators that can be assessed	Does the method allow monitoring of several indicators at once?
Type III: The level of confidence in the obtained data	Aim: keeping the reliability at an acceptable and stable level compared to the present method Required analysis: accuracy and consistency of the data based, e.g., on the technology readiness level (TRL)
Type IV: Value of data	How well does the data fit the requirements of an indicator compared with the present method? Ultimately, the true value of monitoring data comes from the benefits gained from its use. Thus, even a rapid and low-cost method is not truly cost-efficient if the data is not representative of the environmental factor that is being monitored.