Sportsbooks set the handicap lines for individual golfers in a tournament by employing a combination of statistical analysis, market research, and expert insights. Initially, they evaluate a golfer's past performance metrics, including scoring averages, consistency, and how they have fared against competition in similar conditions or courses. They also take into account factors like course difficulty, conditions on tournament day, and player form leading up to the event. Market sentiment is another critical component; sportsbooks monitor public betting patterns and adjust lines to manage risk and balance their books.