The reality of reduction experiments and the GIUR: reply to Eren and Sampson

There is no ambiguity in the existing empirical support for a GIUR as a robust predictor of mass lost from flakes through unifacial retouching. We demonstrate why the GIUR is a reliable method for inferring mass loss, in appropriate circumstances, and why it is a more powerful predictor of mass loss than touted competitors. We explain why Eren, M.I., Sampson's, G. [2009. Kuhn's geometric index of unifacial stone tool reduction (GIUR): does it measure missing flake mass? J. Archaeol. Sci.] arguments are faulty and why researchers should use the GIUR in preference to other methods of estimating the extent of unifacial retouch.