The technique of debitage mass analysis based upon size grades of debitage populations is shown to be prone to errors when making interpretations about the kind of tool produced or the kind of lithic reduction technology used. Significant sources of error may originate from differences in individual flintknapping styles and techniques, raw material size and shape variants, and mixing of debitage from more than one reduction episode. These sources of error render debitage Mass Analysis ineffective for determining the kind of stone tool reduction activities practiced at excavated sites. Mass Analysis may be effective for determining artifact reduction sequences if it is used on debitage from a single reduction episode or part of a reduction episode. However, it is shown that Mass Analysis when used for assessing reduction sequence information, must also control for the effects of raw material variability, assemblage mixing, and flintknapping styles.