Ratcliff/Obershelp pattern recognition


Definition: Compute the similarity of two strings as the number of matching characters divided by the total number of characters in the two strings. Matching characters are those in the longest common subsequence plus, recursively, matching characters in the unmatched region on either side of the longest common subsequence.

Generalization (I am a kind of ...)
string matching with errors.

Author: PEB

More information

John W. Ratcliff and David Metzener, Pattern Matching: The Gestalt Approach, Dr. Dobb's Journal, page 46, July 1988.

Go to the Dictionary of Algorithms and Data Structures home page.

If you have suggestions, corrections, or comments, please get in touch with Paul E. Black.

Entry modified 17 December 2004.
HTML page formatted Fri Mar 25 16:20:35 2011.

Cite this as:
Paul E. Black, "Ratcliff/Obershelp pattern recognition", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed., U.S. National Institute of Standards and Technology. 17 December 2004. (accessed TODAY) Available from:

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