  A new evaluation of the universal $\pi\pi$ scattering length relation is used
to extract the $\pi\pi$ $s$-wave scattering lengths from threshold pion
production data. Previous work has shown that the chiral perturbation series
relating threshold pion production to $\pi\pi$ scattering lengths appears to
converge well only for the isospin-2 case, giving $a_2 = -0.031\pm 0.007
m_\pi^{-1}$. A model-independent and data-insensitive universal curve then
implies $a_0 = 0.235\pm 0.03 m_\pi^{-1}$ for the isospin-0 scattering length.
