On calculating the reliability of the comparative method at long and medium distances

The high degree of contradiction and incompatibility between two independently produced Afroasiatic comparative lexica (Ehret 1995, Orel & Stolbova 1995) calls into question the reliability of the comparative method at deep time depths. The discrepancy could only have arisen if one or both sources contain a large number of chance or spurious matches. This article first documents the discrepancy between the two comparative lexica, and then attempts to explain it. The central proposal is that the evaluation of a proposed reconstruction must go beyond qualitative evaluations of individual proposed cognate sets and incorporate quantitative tools for evaluating the probable degree of chance matches within the reconstruction as a whole.