Best practices for finding specific words in documents

Hi, One of my team's use cases with Textract is to use the presence of a certain word in the document to categorize the documents. We do this using a query - "Is <word> in the document?". We tested this extensively with several test documents and it never returned an incorrect response.

However, in production, we started noticing that Textract returned "Yes" for many documents even though the specific word was nowhere to be found in them. The confidence scores for these false positives go up to 65%, so setting a threshold on that can potentially reject true positives as well.

I wanted to know if there are any best practices around this type of query and how I can improve its accuracy. I would also appreciate any insight into how and where Textract finds values from the document, like whether it looks into metadata or employs any sort of edit distance matching to find words.