# How Spelling Correction Works

To enable spell checking, set the parameters `SpellCheckMaxCheckTerms`, `SpellCheckIncorrectMaxDocOccs`, and `UnstemmedMinDocOccs` in the `[Server]` section of the configuration file before you index content. When you perform a query that includes `Spellcheck=True`, the IDOL Content component uses these settings in the spell checking process, as shown below:

1. Content determines if the query is eligible for spell checking.

   Content checks how many terms the query text contains (it ignores stop words, proper-name terms and hyphenated terms). If the number does not exceed the specified `SpellCheckMaxCheckTerms`, the query is eligible for spell checking.

2. Content determines which terms are misspelled.

   Content checks how many times each query term occurs in its data index. If a term occurs fewer times than the specified `SpellCheckIncorrectMaxDocOccs`, Content assumes that the term is misspelled.

3. Content finds correct spellings and suggests them.

   Content uses a proprietary term-distancing algorithm to find terms in its data index that are closest to the misspelled terms. It then checks how many times these terms occur. If a term occurs at least the specified number of `UnstemmedMinDocOccs` times, it uses it as a spell check suggestion.

   Content returns the corrected terms as a comma-separated list in an `<autn:spelling>` field. It also returns a corrected version of the query text in an `<autn:spellingquery>` field.

4. When you shut down the IDOL Content component, it creates a spelling correction file.

   The spelling correction file stores the corrections that you make. You can add further corrections to the file or amend existing corrections.

Related Topics

- Spelling Correction File

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