Few saw it coming when Phil Mickelson and caddie Jim “Bones” Mackay parted ways last year after more than 25 years together. The two were one of the most successful and recognizable player/caddie duos in golf history. Bones had Phil’s bag for 40 PGA Tour wins and five majors.

That got us thinking: how do Tour players perform after changing a caddie? Does a new looper result in improved performance?

We looked at a handful of notable caddie switches from Tiger Woods, Lefty, Matt Kuchar, Adam Scott and Fred Couples. Some sample sizes were better than others but, for the five golfers we looked at, all improved by switching to their main caddie, and all but two saw drastic drop-offs after switching from a caddie that had been on their bag for more than 100 events. Of course, there are other circumstances affecting those changes, but it'd be hard to say that caddie switches don't have a noticeable effect.

Here are some other notable takeaways from the data:

Tiger Woods placed in the Top 3 in almost half of all the events he played in with Steve Williams. That's absurd.

Tiger also finished in the Top 25 more often than most other golfers even made the cut while he was playing with Williams. That is also absurd.

Adam Scott and Matt Kuchar are the only two golfers on this list who got better after switching from their longtime caddie, with Kuchar barely improving, and Scott playing the best golf of his career since switching.

With Bones on his bag, Phil Mickelson played more events than every other golfer on this list has played in their careers, other than Fred Couples.

Tiger Woods

Events played 1st place Top 3 Top 10 Top 25 Made cut With Fluff Cowan 65 12.31% 27.69% 47.69% 64.62% 84.62% With Steve Williams 202 31.19% 48.02% 67.33% 88.12% 97.03% Since 57 14.04% 21.05% 31.58% 47.37% 80.70%

Fluff Cowan was Tiger Woods’ first-ever PGA Tour caddie, carrying the bag for the young phenom first at the 1996 Greater Milwaukee Open. The pair had 65 Tour events and one major win (the 1997 Masters) under their belts together when, in February of 1999, they split. Woods’ next caddie would be his most famous — Steve Williams.

Woods and Williams partnered for the 1999 Bay Hill Invitational and saw 202 events before their professional relationship ended in July of 2011.

So how did Woods do in the three eras of his caddies?

With Williams, Woods won outright in a ridiculous 31.2 percent of the tournaments he played. What’s more, he finished in the Top 3 at PGA Tour events 48 percent of the time. That’s more often than he finished in the Top 10 with Fluff (47.7 percent) or the Top 25 after splitting with Williams (47.4 percent). With Steve on his bag, Tiger finished in the Top 10 in roughly two out of every three events he played (67.33 percent), and made the cut 97 percent of the time.

When it comes to majors, Woods’ career with Williams rises above the rest again. Tiger played in 47 majors with Williams, made the cut in 95 percent of them, and won outright in 13.

Since parting ways with Williams in 2011, Woods has played 57 events, made the cut in 80.7 percent of them, and won 14 percent.

With Tiger, it’s hard to say how much of an effect a specific caddie played on his success, but if numbers told the whole story, Williams’ connection with Woods was unmatched in their day.

Phil Mickelson

Events played 1st Top 3 Top 10 Top 25 Made cut Before Bones Mackay 12 8.33% 8.33% 8.33% 16.67% 66.67% With Bones Mackay 545 7.52% 18.53% 33.94% 55.78% 84.77% Since 7 0.00% 0.00% 14.29% 42.86% 71.43%

With Bones, Mickelson finished in the Top 10 of 56 percent of the tournaments he played, and made the cut for 85 percent of them. Because of how impressively long Bones’ tenure as Lefty’s looper was, the sample size for pre- and post-Bones isn’t large enough to extrapolate from, but it’s safe to say Mickelson’s career was impacted for the best by his longtime caddie.

Adam Scott

Events played 1st Top 3 Top 10 Top 25 Made cut Before Tony Navarro 43 4.65% 9.30% 18.60% 34.88% 62.79% With Tony Navarro 128 3.91% 12.50% 27.34% 44.53% 80.47% Since 110 5.45% 12.73% 38.18% 64.55% 91.82%

Tony Navarro spent 13 years looping for Greg Norman before Adam Scott hired him away in the spring of 2004. The pair were together for 128 Tour events before eventually splitting in May of 2011. And it looks like the move was a smart one for Scott.

With Navarro, Scott placed in the Top 25 of 45 percent of his events. In the 110 events since their split, that number has jumped to 65 percent. Scott has made 92 percent of cuts since parting ways with Navarro, up from 80 percent and, in 2013, after 28 unsuccessful tries with his previous caddie, Scott won his first major — the Masters. And who happened to be on his bag for that win? None other than Steve Williams, of course.

Fred Couples

Events played 1st Top 3 Top 10 Top 25 Made cut Before Joe LaCava 240 1.25% 6.25% 24.17% 49.58% 79.58% With Joe LaCava 358 3.35% 11.17% 29.05% 49.16% 81.01% Since 15 0.00% 0.00% 0.00% 26.67% 60.00%

Fred Couples is somewhat of an enigma here. The former World No. 1 played the majority of his career — more than 300 PGA Tour events — with caddie Joe LaCava, but saw very little difference between that span, and the 240 events prior to it. LaCava and Couples began in 1990, and between then and 2011, when they split, Couples placed in the Top 25 in 49.2 percent of events, down from 49.6 percent before LaCava. With LaCava, Couples made the cut in 81 percent of his tournaments, and 80 percent of his majors, virtually the same as pre-LaCava (79.6 percent and 83.3 percent respectively).

Couples did win his lone major with LaCava at the 1992 Masters, but if there’s one thing that these stats show, it’s just how consistent Boom Boom is, regardless of who’s on the bag.

Incidentally, after the split with Williams, Tiger Woods turned to the services of LaCava, and Couples encouraged the move. Unfortunately for Woods and LaCava, much of their time together has been marred by Woods' list of injuries.

Matt Kuchar

Events played 1st Top 3 Top 10 Top 25 Made cut Before Lance Bennett 155 0.65% 2.58% 6.45% 16.13% 48.39% With Lance Bennett 195 3.08% 10.77% 33.33% 59.49% 86.67% Since 51 0.00% 7.84% 35.29% 62.75% 88.24%

Matt Kuchar and Lance Bennett linked up in 2008, and were paired off until 2016, playing in almost 200 PGA Tour events together.

Kuchar is the lone player on this list to have not won a major, but there’s no denying his vast improvement in major play with Bennett on the bag. Before Bennett, Kuchar made the cut in just 23 percent of his majors, while with Bennett, that number skyrocketed to 81 percent and even saw seven Top 10 finishes.

That wasn’t the only thing that improved with the new caddie in 2008. Kuchar’s Top 25 finishes leapt from just 16 percent pre-Bennett, to 59.5 percent with him. He made the cut almost twice as often (87 percent from 48 percent) and had more than five times as many Top 3 finishes in roughly the same number of tournaments. Like Mickelson, Kuchar’s had a limited sample size since his split with Bennett, but it would be hard to say the longtime caddie didn’t have a great impact on his golfer.