Typo Tolerance

On this page

• What is typo tolerance?
• How typos are calculated
  • Calculating distance
  • Calculating term frequency

What is typo tolerance?

Typo tolerance is a feature that allows a system to recognize and correct typing errors made by users.

Typo tolerance is fundamental to modern search experiences by reducing frustration caused by small typing mistakes. It can save time and effort for users who may not have realized they made an error and can improve the accuracy of search results. For example, if a user misspells a word in a search engine, the search engine will suggest the correct spelling or provide results that match the intended word.

Additionally, it can help users with disabilities or those using non-standard keyboards to more easily access information.

• Note: Boost Typo tolerance algorithms use various techniques to handle different types of errors, such as swapping adjacent letters, omitting or adding letters, or substituting similar-looking characters. These algorithms are constantly improving with advancements in natural language processing and machine learning.

• Note: This feature is only available for App Lib V3, please contact us for further instructions.

How typos are calculated

Boost’s typo tolerance algorithm for dealing with typos is based on 2 factors:

• The difference in spelling between a query word and its exact match in the index (the “edit distance”).
• The term frequency: our algorithm will consider a term that appears more frequently in your catalog to rank higher.

Calculating distance

Distance is the difference in spelling between a query word and its exact match in the index.

For example,

The query “Sok” may mean “sock” (edit distance =1)

The query “Refelctive” may mean “Reflective” (edit distance = 1) The query “maintainance” may mean “maintenance” (edit distance = 2)

The query “computr covre” may mean “computer cover” (edit distance = 2)

Note: The smaller the distance of a spell-correct candidate is to the original query, the higher it will rank. It helps determine which term is closest to what the user entered.

Calculating term frequency

The typo tolerance algorithm prioritizes the term that appears more frequently in your catalog as the probable candidate for spell correction.

Suppose your customer enters the query "shrts," and the corrected spellings are "shirts," "shorts," and "shoes." If the term "shorts" appears more frequently in your catalog than "shirts," then the typo tolerance algorithm will correct the query to "shorts.”