All calculations have been done using the hyperspherical harmonics (HH) method as developed by some of the authors to describe bound and scattering states in A = 3 , 4 systems [16–19] in configuration space or in momentum space [20, 21] (for a recent review see Ref. [13]). The paper is organized as follows. In the next section we introduce the TNF models in configuration space defining their parametrizations. In Section III we make a sensitivity study of the parametrization for each model looking at B ( $^{3}$H), B ( $^{4}$He) and $^{2}$a$_{nd}$ . In Section IV we study p − d polarization observables at E$_{lab}$ = 3 MeV for specific values of the parameters. The conclusions are given in the last section. In Ref. [13] the description of bound states and zero-energy states for A = 3 , 4 has been reviewed in the context of the HH method. In Table I we report results for the triton and $^{4}$He binding energies as well as for the doublet n − d scattering length $^{2}$a$_{nd}$ using the AV18 and the N3LO-Idaho NN potentials and using the following combinations of two- and three- nucleon interactions: AV18+URIX, AV18+TM’ and N3LO-Idaho+N2LOL. The results are compared to the experimental values also reported in the table. Worthy of notice is the recent very accurate datum for $^{2}$a$_{nd}$ [22]. From the table we may observe that only the results obtained using an interaction model that includes a TNF are close to the corresponding experimental values. In the case of the AV18+TM’, the strength of the TM’ potential has been fixed to reproduce the $^{4}$He binding energy and, as can be seen from the table, the triton binding energy is underpredicted. Conversely, the strength of the URIX potential has been fixed to reproduce the triton binding energy, giving too much binding for $^{4}$He. The strength of the N2LOL potential has been fixed to reproduce simultaneously the triton and the $^{4}$He binding energies. In the three cases the predictions for the doublet scattering length are not in agreement with the experimental value, in particular for the AV18+URIX model. Our intention is to study different parametrizations of the TNFs to obtain, as close as possible, a simultaneous description of the three quantities under observation. To this aim we give a brief description of the TM’ (or Brazil), URIX and N2LOL models. Starting from 4 II. THREE NUCLEON FORCE MODELS