Web Search Overview Crawling IR Comparing Text Comparing the query text to the document text and determining what is a good match is the core issue of information retrieval Exact matching of words is not enough Many different ways to write the same thing in a "natural language" like English e.g., does a news story containing the text "bank director in Amherst steals funds"match the query? Some stories will be better matches than others 8Web Search Overview & Crawling 8 Comparing Text ▪ Comparing the query text to the document text and determining what is a good match is the core issue of information retrieval ▪ Exact matching of words is not enough ▪ Many different ways to write the same thing in a “natural language” like English ▪ e.g., does a news story containing the text “bank director in Amherst steals funds” match the query? ▪ Some stories will be better matches than others IR