The CHeReL currently uses Choicemaker software for linkage.
Choicemaker provides for standardisation and parsing, and differs
from the classical probabilistic approaches and software
primarily in the use of an automated blocking algorithm and machine
learning technique for 'scoring' or assigning weights. The system
also allows users to make use of stacked data (where multiple
values are present in a single field) and includes a "transitivity
engine" that allows for a user-specified action in the case of
transitive linkage problems - for example, if record A is a high
probability match to both B and C, but B and C are low probability
matches to each other. More detail on these features is described
in Goldberg and Borthwick (2004). Additional advantages of
Choicemaker for the CHeReL are that the system is multi-user,
matches in one rather than several steps, is capable of matching
very large files and can be run on variety of platforms.