# Introduction

Pre-filtering allows you to narrow down the amount of input text that Eduction processes for a particular set of entities. With pre-filtering, Eduction performs an initial quick matching step that finds sections of text that contain likely matches, rather than running the full match on the whole input.

Pre-filtering text can improve performance for some entities, when there is a broad way to find a potential match without either over-matching too much of the input text, or eliminating potential valid matches. For example, if you want to match addresses, you can use pre-filtering to find numbers in the text (which might correspond to house numbers or postal codes).

This method is less useful for entities that match a list of possible words (such as names), when there is no simple regular expression that matches all your possible entities.

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