  In his Comment on a recent paper by two of us Kominis claims that the
recently proposed quantum measurement model for spin-selective reactions of
radical pairs leads to ambiguous predictions in a simple case. Here we show
that this claim is based on a confusion between the unreacted and unrecombined
portions of the radical pairs, and to an incorrect interpretation of the
improper density matrices used in both our model and the conventional Haberkorn
model of such reactions. We further show that if this error is corrected then
the supposed ambiguity is resolved.
