Match rating approach

<h2 id="encoding-rules">Encoding rules</h2>
<ol><li>Delete all vowels unless the vowel begins the word</li>
<li>Remove the second consonant of any double consonants present</li>
<li>Reduce codex to 6 letters by joining the first 3 and last 3 letters only</li></ol>
<h2 id="comparison-rules">Comparison rules</h2>
<p>In this section, the words "string(s)" and "name(s)" mean "encoded string(s)" and "encoded name(s)".
</p>
<ol><li>If the length difference between the encoded strings is 3 or greater, then no similarity comparison is done.</li>
<li>Obtain the minimum rating value by calculating the length sum of the encoded strings and using table A.</li>
<li>Process the encoded strings from left to right and remove any identical characters found from both strings respectively.</li>
<li>Process the unmatched characters from right to left and remove any identical characters found from both names respectively.</li>
<li>Subtract the number of unmatched characters from 6 in the longer string. This is the similarity rating.</li>
<li>If the similarity rating is equal to or greater than the minimum rating, then the match is considered good.</li></ol>
<h2 id="minimum-threshold">Minimum threshold</h2>
<p>The following table shows the mapping between the minimum rating and the string lengths.
</p>
Table A<table><tbody><tr><th>Sum of Lengths</th><th>Minimum Rating</th></tr><tr><td>≤ 4</td><td>5</td></tr><tr><td>4 < sum ≤ 7</td><td>4</td></tr><tr><td>7 < sum ≤ 11</td><td>3</td></tr><tr><td>= 12</td><td>2</td></tr></tbody></table>
<h2 id="match-rating-approach-examples">Match rating approach examples</h2>
<p>The table below displays the output of the match rating approach algorithm for some common homophonous names.
</p>
<table><tbody><tr><th>Name</th><th>MRA Codex</th><th>Minimum Rating</th><th>Similarity Comparison Rating</th></tr><tr><td>Byrne</td><td>BYRN</td><td rowspan="2">4</td><td rowspan="2">5</td></tr><tr><td>Boern</td><td>BRN</td></tr><tr><td>Smith</td><td>SMTH</td><td rowspan="2">3</td><td rowspan="2">5</td></tr><tr><td>Smyth</td><td>SMYTH</td></tr><tr><td>Catherine</td><td>CTHRN</td><td rowspan="2">3</td><td rowspan="2">4</td></tr><tr><td>Kathryn</td><td>KTHRYN</td></tr></tbody></table>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Soundex/1EL8PN6b">Soundex</a></li></ul>

<h2 id="external-links">External links</h2>

The Wikibook <i>Algorithm_implementation</i> has a page on the topic of: <i>Match rating approach</i>

<ul><li><a href="http://www.statcan.gc.ca/pub/85-602-x/4193729-eng.pdf">An Overview of the Issues Related to the Use of Personal Identifiers, HSMD, Statistics Canada</a></li>
<li>C# Implementation: <a href="http://sounditout.codeplex.com/">http://sounditout.codeplex.com/</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Moore, G B.; Kuhns, J L.; Treffzs, J L.; Montgomery, C A. (Feb 1, 1977). Accessing Individual Records from Personal Data Files Using Nonunique Identifiers. US National Institute of Standards and Technology. p. 17. NIST SP - 500-2. <a href="https://archive.org/details/accessingindivid00moor" target="_blank">https://archive.org/details/accessingindivid00moor</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
</ol>

Match rating approach open-in-new

Match rating approach