---
title: Troubleshooting thesaurus and stop words rules
slug: o6jb0124
canonical_url: https://docs.coveo.com/en/o6jb0124/
collection: tune-relevance
source_format: adoc
---
# Troubleshooting thesaurus and stop words rules

The information provided on this page can help you identify and resolve issues with thesaurus rules impacting partial match parameters.
However, keep the following in mind:

* A given set of behaviors, such as unexpected search results, can be caused by different underlying issues.

* If one or more [query pipeline rules](https://docs.coveo.com/en/236/) aren't behaving as you expect, you can find useful troubleshooting information in the [execution report](https://docs.coveo.com/en/2088#access-the-execution-report), that contains detailed information about the rules that were applied to a [query](https://docs.coveo.com/en/231/).

Use the following guidelines to troubleshoot your issue before you contact [Coveo Support](https://connect.coveo.com/s/case/Case/Default) for help.

## Thesaurus entries impacting partial match parameters

* [thesaurus](https://docs.coveo.com/en/2742/) rules can affect the way [partial match](https://docs.coveo.com/en/2858/) interacts with a query.

* The `partialMatchKeywords` and `partialMatchThreshold` parameters determine the results from [keywords](https://docs.coveo.com/en/2738/) found in the query.

* A thesaurus rule that alters the number of keywords in the [basic query expression (`q`)](https://docs.coveo.com/en/178/) can affect the partial match parameters.

### Potential cause

Let's say your query pipeline contains the following query parameter rules:

* `partialMatch`: true

* `partialMatchKeywords`: 3

* `partialMatchThreshold`: 66%

![Create partial match rules | Coveo Platform](https://docs.coveo.com/en/assets/images/tune-relevance/partial-match-rule.png)

This means that the partial match would activate if there are a minimum of three keywords in [basic query expression (`q`)](https://docs.coveo.com/en/178/) and two-thirds of the words in the queries are keywords.

However, a **Synonym** thesaurus rule like `include water, eau, agua, pond, lake... when any are present` can transform the `q` to a version that doesn't meet the 66% threshold, returning no results.

![Create thesaurus synonym rule | Coveo Platform](https://docs.coveo.com/en/assets/images/tune-relevance/thesaurus-synonym-rule.png)

The [**Relevance Inspector**](https://platform.cloud.coveo.com/admin/#/orgid/search/relevanceInspector/) ([platform-ca](https://platform-ca.cloud.coveo.com/admin/#/orgid/search/relevanceInspector/) | [platform-eu](https://platform-eu.cloud.coveo.com/admin/#/orgid/search/relevanceInspector/) | [platform-au](https://platform-au.cloud.coveo.com/admin/#/orgid/search/relevanceInspector/)) shows the `basicExpression` has been transformed as per the thesaurus rule, thus not respecting the partial match parameters anymore and giving no (zero) results.

![No result in Relevance Inspector with synonym rule| long query-expression | Coveo Platform](https://docs.coveo.com/en/assets/images/tune-relevance/relevance-inspector-no-result.png)

### Resolution

In such a case, it's better to change the thesaurus rule from **Synonym** to **Replace**.
By using the same words in the thesaurus rule, it's possible to change the interaction of these two rules by changing the type of rule from **Synonym** to **Replace**.

![Create thesaurus replace rule | Coveo Platform](https://docs.coveo.com/en/assets/images/tune-relevance/thesaurus-replace-rule.png)

When the query `agua fire earth` is searched this time, it will be transformed by the thesaurus rule into `water fire earth`.

![Result set in Relevance Inspector with replace rule | short query-expression | Coveo Platform](https://docs.coveo.com/en/assets/images/tune-relevance/relevance-inspector-after-rule-change.png)

The `basicExpression` will be the same even if the user enters any of the other words mentioned in the thesaurus rule.
Hence, the version of the query after the thesaurus rule will respect the partial match parameters.