This option weights (prioritizes) the search results by a score that is calculated on the percentage of the job description that contains words that match your search terms. For example, compare a job (Job "A") containing 100 words in the description where the word 'accounting' appears 3 times to another job (Job "B") with 1000 words in the description where the word 'accounting' appears 5 times. Job "B" has the desired search term more often, but it occupies less of a percentage of the total job description, so Job "B" would score lower.