The Tonocap device had bias and precision values of −2.6% and ±1.4%.
Soon all woods had bias built in, originally achieved by appropriate weighting, later by shaping one side of the wood to be less round than the other.
Even models that adjusted deposition estimates based on deposition measurements to reduce bias or that spatially-interpolated measurement data, had bias that approached or exceeded critical loads at some locations.
The bias was of the same magnitude, a few t/ha, although with opposite signs, and the accuracy and correlation was only slightly better with alternative 4. The two alternatives in between, i.e. alternatives 2 and 3, had bias and accuracy values of fairly the same magnitude.
Specifically, all parameter estimates and their standard errors had bias less than 5%, coverage of all parameter estimates was within the recommended range of 0.91 0.98, and power was higher than 0.8 for all parameter estimates, except for two factor covariances of small effect sizes.
