4 Types of Keyword Matches
This is a broadly matched search query.
This is a search query that matched in part.
This is an exact matched query.
Why Keyword Matches Matter for Determining a Document's Relevance.
The Keyword Match Ranking Function
An anecdotal analysis can provide some insight as to why various types of matches matter more or less than others. The exact degree will always be subjective and probably be tweaked from now til the end of time. Perhaps an algorithm can compute different analysis of keyword matches based on the actual search query topic. The problem in measuring match types and assigning relevancy values is not in the lack of computing abilities, but rather in the fact that often times a searcher isn't quite sure what they are searching for and may rely on the search engine for delivering results that are unexpected but satisfactory.
The creation of a ranking function based on keyword matches relies heavily on vector analysis. A dose of matrix operations are implemented to determine how much particular keywords are valued based on the match type. An understanding of dot products and cross products are required to fully grasp the keyword match type ranking function.
Let's start with a simple example where documents are ranked based on one concept. The degree to which the search query matches the text in the documents. In this example, we shall ignore keyword frequency and all other potential ranking factors. We shall ignore the case of a tie, where 2 results share the same match.