In addition to the words and codes in Names, Addresses, Titles and Descriptions, we frequently use other data to make decisions about whether we believe two reports or records are about the same entity.

Search for	ROBERT J. JOHNSTON	12 RIVER SIDE SPRINGVALE	(807) 2334 657	1962/02/12
Yes	BOB JAMES JOHNSTON	SPRING VALE	2334 657	1962
May be	MR. R. J. JOHNSTONE	35 CITYVIEW CT. SPRINGVALE	1 807 4456 721	1962/12/02
No	ROBERT JOHNSON	2 MAPLE RD. BROOKFORD	555 763 2413	1973/10/04

Data such as dates of birth, dates of contract, ages, phone numbers and identity numbers are all subject to error and variation.

When a name is used to bring up candidates on a screen, people use all of the identification data returned to choose whether the records displayed are relevant or appropriate. In automated matching systems, the system itself has to be able to use the same data that people would use.

When people make choices about whether things match or not, they compensate for the error and variation. Our systems have to achieve the very same compensation that people make.

To confirm that records are in fact matching requires that our systems use the same data in the same manner as the human users of our systems would use. In fact our systems need to mimic our very best users doing the same job.