  Spectral lags are deduced for 1437 long GRBs with peak fluxes extending to
near the BATSE trigger threshold. The lags are modeled to approximate the
observed distribution in the peak flux-lag plane, realizing a noise-free
representation. Assuming a two-branch lag-luminosity relationship, the lags are
self- consistently corrected for cosmological effects to yield distributions in
luminosity, distance, and redshift. The results have several consequences for
GRB populations -- including a possible nearby subpopulation of low-luminosity,
long-lag GRBs -- and for unified gamma-ray/afterglow scenarios which would
account for afterglow break times and gamma-ray spectral evolution in terms of
jet opening angle, viewing angle, or a profiled jet with variable Lorentz
factor.
