The Masters Golf Tournament required the use of local caddies from the Augusta National Golf Club from 1934 through 1982. Since 1983, golfers at the Masters Tournament have been able to use their tour caddies. An economic paper in 2014 by Douglas Coate and Michael Toomey asked if professional golf caddies improve player scoring.
They compared player scoring for the three years before the change (1980-1982) to the three years after the rule change (’83-‘85). They also took into account player quality (by position on the PGA Tour money list), weather conditions as provided by the PGA Tour, as well as round indicators (first, second, third, fourth). For each round, they identified whether the caddie was local or on tour.
Their estimates suggest that players scored about 0.6 to 0.8 strokes lower in the tour caddy era. However, this difference was not as large as at the Western Open at Butler National golf club in Oak Brook, Ill., where tour caddies helped lower golfers’ scores by 1.2 shots per round.
This suggests the Augusta National caddies score improving skills were superior to the local Western Open caddies, but not those of tour caddies.
Readers who are interested in learning more about the local Augusta National caddies can read the book, Men on the Bag: The Caddies of Augusta National by Ward Clayton. The movie, Loopers: The Caddies Long Walk, narrated by Bill Murray has a section on the Augusta National caddies and is also worth watching.