Comparison Algorithms

NameSearch® comparison algorithms determine numeric values that represent the likelihood of a match. Two entities are passed to the comparison routine and a score or array of scores are returned.

There are many ways of calculating a score. William Jefferson Clinton versus Bill Clinton would yield as scores; 100, 50, 66 and 33. The basic approach is to divide the number of tokens by the number of matches and multiply that figure by 100. In the previous example the number of tokens is either two or three words. Bill Clinton has two tokens and William Jefferson Clinton has three. The only word that matches exactly is Clinton. Dividing the number of tokens by the number of matches and multiplying by 100 we get (1/2 * 100 = 50) and (1/3 * 100 = 33). Alternatively, Bill and William are used interchangeably and can be considered to match. In this instance the scores would be (2/2 *100 = 100) and (2/3 * 100 = 66).

The score or scores that are used to determine the likelihood of a match, depend on the degree of accuracy required by your system. Scoring is essential in on-line applications, where the number of records returned is too great for a person to scan or batch utilities, where decisions based on the likelihood of a match invoke automated processes.

NameSearch Comparison Algorithms

ALFACOMP
This is used to compare fields containing multi word strings. The ALFACOMP routine is based solely on a heuristic algorithm and is not dependent on rulebase expertise.

DATESCR
The Date Score is used for comparison of two dates. The DATESCR comparison routine uses rulebase expertise in order to arrive at its’ results. For example, July 28, 1965 compared to 7/28/66 would yield a score of 100 in this matter the DATESCR routine overcomes problems due to inconsistency in date format. The routine also accepts several parameters which will dictate the penalty for mis-matches based on the year. By increasing these settings the score can be made more tolerant. For example, if you want all dates that correspond to July 28, 1965 + or - two years, you would set the year range to 2. If you wish it to be + or - five years this would mean your year range would be set to 5. In this manner NameSearch gives you the ability to widen or narrow the range of dates being returned given the month a day agrees.

NUMCOMP
This is a comparison routine used for evaluating Alpha numeric strings. For example this routine is well suited for Social Security number comparisons.

COMP, COMP1, COMP2
These are NameSearch’s comparison routines used for scoring names and addresses. These routines utilize NameSearch’s rulebase expertise and phonetic tokenization to determine scores. Comp was the original comparison routine released with version 1 of the NameSearch product. COMP1 was introduced in Version 2.0 of the NameSearch product in order to provide a more representative score. In Version 2.5 of the NameSearch product COMP2 was added. This routine uses ALFACOMP, an advanced heuristic algorithm, to arrive at its results.