Table 7

Observed and calculated prevalences at the time of the first survey by Bovenzi [31] predicted by models when fitting both non-zero data points and zero prevalence at zero time (top row, using calculated expfac or fitted expfac), and when using one non-zero data point and zero prevalence at zero time (second and third rows using calculated expfac). is a fitted parameter in both models. expfac is also a fitted parameter in the model using equation (4) with the 4th-order parameters.

		Calculated expfac (using Eq. (4))			Fitted expfac (using Eq. (3) with the 4th-order parameters)
	Prevalence of “unknown” data point (at t = 15 years)/%	q		Calculated prevalence/%	expfac		Calculated prevalence/%
Both data points (stone workers)	38.2	0.308	1.027	38.2	1.32	1.03	38.3
Only one data point (stone workers)	38.2	0.3	1.04	38.2	n/a	n/a	n/a
Only one data point (forestry workers)	14.0	0.3	0.024	14.0	n/a	n/a	n/a