- The γ(t) rate is either a constant (cte) or a sigmoid function of time (var), and the datasets used in the fit (27) include IPs and Ns in all cases, and additional data on IPPs in cases 3 and 4. The parameter values obtained from optimization are highlighted in blue. The corresponding a priori criterion values are highlighted in red. The values of the criterion recomputed a posteriori with adding (upper line) or removing (lower line) the IPP dataset are left in black