  We use simple analytic considerations and a Monte Carlo calculation of
nucleons in a box to argue that the use of Jastrow functions as short-range
correlators in the commonly employed two-body-cluster approximation causes
significant errors in the matrix elements for double-beta decay. The Jastrow
approach appears to agree with others, however, if many-body clusters are
included. A careful treatment of the charge-changing analog of the nuclear pair
density shows, in addition, that differences between Unitary Correlator
Operator Method and Brueckner methods for treating short-range correlations in
double-beta are less significant than suggested by previous work.
