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Comparison: Character Match Percentage

The Character Match Percentage comparison determines how closely two values match each other by calculating the Character Edit Distance between two String values, and also taking into account the length of the longer or shorter of the two values, by character count.

In mathematical terms, the Character Match Percentage comparison uses the following formula to calculate its results:

where:

CMP = Character Match Percentage

MCL = Maximum Character Length of the two values being compared, in characters

CED = the Character Edit Distance between two String values, and

CL =  either the Maximum or Minimum Character Length, depending on the setting of the Relate to shorter input option. If Relate to shorter input is set to No (as by default), the Maximum Character Length is used. If Relate to shorter input is set to Yes, the Minimum Character Length is used (that is, the number of characters in the shorter of the two values by character count).

So, for the pair of values "ABC" and "ABCD":

CED (Character Edit Distance) = 1

MCL (Maximum Character Length = 4, and

mCL (Minimum Character Length) = 3

So, if the Relate to shorter input option is set to No, the Character Match Percentage (CMP) is calculated as follows:

MCL (4) - CED (1) = 3, divided by MCL (4) = 0.75, multiplied by 100 =  75%.

If Relate to shorter input is set to Yes, the calculation is different:

MCL (4) - CED (1) = 3, divided by mCL (3) = 1, multiplied by 100 = 100%.

Use

Use the Character Match Percentage comparison to find matches where values are of varying lengths (such as names), and there might be spelling mistakes in the original values. For example, when matching company names, the values "ABC" and "BBC" have a Character Edit Distance of 1, and might be deemed a close match by other comparisons. However, their Character Match Percentage is only 66%, whereas the Character Match Percentage of "Oracle" and "Oracles", which also have a Character Edit Distance of 1, is 90%, indicating a stronger match.

This comparison supports the use of result bands.

Options

Results

This comparison calculates a percentage value indicating the level of similarity between two string values, expressed as percentage similarity.

This comparison supports the use of result bands.

Example

Example configuration

In this example, the Character Match Percentage comparison is used to match company names. The following options are specified:

Match No Data pairs? = No

Ignore case? = Yes

Relate to shorter input? = No

The following transformations are added:

1. Trim Whitespace, to remove all whitespace from values before comparing them
2. Strip Words, using *Business Suffix Map (which includes the words 'Ltd' and 'Limited')

Example results

The following table illustrates some example comparison results using the above configuration: