We show that it makes sense to coarse grain hadronic

interactions such as $\pi\pi$ and $\pi N$ reactions following

previous work on NN scattering. Moreover, if the interaction is

taken to be given by chiral dynamics at long distances above a given

value $r > r_c$ larger than the elementary radii of the interaction

hadrons the unknown short distance region $r< r_c$ is charecterized

by a {\it finite} number of fitting parameters. This number of

independent parameters needed for a presumably complete description

of scattering data for a CM energy below $\sqrt{s}$ has been found

to be given by $N_{\rm Par} = N_S \times N_I \times (p r_c )^2 /2 $

with $N_S$ and $N_I$ the number of spin and isospin channels, and

$p$ the CM momentum respectively. Therefore, for an experiment (or

sets of experiments) with a total number of data $N_{\rm Dat}$ the

number of degrees of freedom involved in a $\chi^2$-fit is given by

$\nu = N_{\rm Dat}-N_{\rm Par}$ and confidence levels can be

obtained accordingly by standard means. Namely a $1 \sigma$

confidence level corresponds to $\chi_{\rm min}^2/\nu \in (1-

\sqrt{2/\nu},1+\sqrt{2/\nu})$. We discuss the approach for $\pi\pi$

and $\pi N$ with an eye put on a data selection program and the

eventual validation of chiral symmetry.