The WORLD GOLF INDEX describes itself as "an independent performance ranking based on top ten finishes from each major professional golf tour."
It's just a ranking system based solely on performance by comparing professional golfers who compete in specific PGA events. Their results are only reflective of top ten finishes in official PGA tournaments. They assign points to wins and each player is rated as such.
They have their own website at worldgolfindex.org and they have been around since mid-2006.
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