To say the Draft is an inexact science for Major League teams would be an understatement. Of course, that uncertainty is part of what makes it so compelling.

And if a franchise is able to bunch together a few strong first-round picks, the payoff can be huge. That's one way a championship team is built.

To get an idea of which organizations have done this most effectively, we looked back at first-round results in the 30-team era, going back to when expansion Arizona and Tampa Bay participated for the first time in 1996. While the opening round can include extra compensation picks, only top-30 selections who subsequently signed with that team were included in the research. (That does leave out savvy picks just outside the top 30, a list that in recent years includes José Berríos, Jack Flaherty, Joey Gallo, Aaron Judge and Noah Syndergaard).

Obviously, not many players from the past few Drafts have established themselves in the Majors yet, but a 22-year sample from 1996-2017 still provides a meaningful look at the event's challenges and rewards. During that time, clubs signed 638 of those top 30 picks, slightly less than half of whom have produced a positive career Wins Above Replacement (WAR) total according to Baseball-Reference.com. Just 61 of those (9.6 percent) have reached the 20-WAR plateau thus far.

Of course, over the years, some teams have fared better than others at turning high Draft picks into productive Major Leaguers. Here is a look at the five best of those -- in terms of total WAR through 2019 -- plus a few more who appear to be on the rise:

1) Philadelphia Phillies: 199.7 WAR
16 picks (average slot of 13th), 9 with positive WAR

Chase Utley and Cole Hamels became franchise cornerstones. Those two, along with Pat Burrell, Brett Myers and Adam Eaton (the pitcher) had prominent roles on the Phillies' 2008 World Series championship team. More recently, Aaron Nola was a National League Cy Young Award finalist in '18, and Adam Haseley was one of four '17 first-rounders to crack the Majors last season. On the other hand, it still remains to be seen if Mickey Moniak (the top overall pick in 2016) will also help form the core of the future in Philly.

2) Oakland Athletics: 190.6 WAR
27 picks (average slot of 18th), 16 with positive WAR

Mark Mulder and Barry Zito, two-thirds of the team's "Big Three" starting pitchers, were first-rounders. Eric Chavez, Joe Blanton and Nick Swisher also played major roles for Oakland. (The Swisher pick has continued to pay dividends long after his departure). The A's went through a dry spell after 2003 but in the past decade grabbed Sonny Gray, Addison Russell (traded away as a prospect) and slick-fielding third baseman Matt Chapman, who has emerged as a homegrown star. Heralded left-handed pitching prospect A.J. Puk could boost this total even more if he can stay healthy.

3) Arizona Diamondbacks: 183.5 WAR
22 picks (average slot of 15th), 15 with positive WAR

This placement comes with no shortage of frustration, considering that Arizona's most productive pick, Max Scherzer, blossomed after being traded. Justin Upton and Trevor Bauer also went on to star for other clubs, and A.J. Pollock, now a Dodger, has seen a productive career interrupted by frequent injuries. While Archie Bradley has found success in the Majors, he's done so as a reliever, and 2015 No. 1 overall selection Dansby Swanson was dealt away the same year he was drafted.

4) Los Angeles Angels: 176.9 WAR
19 picks (average slot of 18th), 11 with positive WAR

Troy Glaus, the No. 3 overall pick in 1997, was named Most Valuable Player when the Halos beat the Giants in the 2002 World Series. Jered Weaver developed into the club's ace, twice finishing in the top three for the American League Cy Young Award voting. And in Mike Trout, the Angels landed a player who is already first in career WAR among all the top-30 picks from 1996-present, despite being drafted in 2009. The organization's post-Trout picks haven't been especially fruitful thus far, though Jo Adell (No. 10 in '17) is knocking on the door, as MLB Pipeline's No. 6 overall prospect heading into 2020.

5) Minnesota Twins: 168.7 WAR
24 picks (average slot of 15th), 13 with positive WAR

The Twins hit it big with 2001 No. 1 overall pick Joe Mauer, who finished his career with 55.3 WAR -- all in Minnesota. Michael Cuddyer, Denard Span, Matt Garza and Glen Perkins all enjoyed their share of big league success as well, and Aaron Hicks and Kyle Gibson continue to produce. The speedy Byron Buxton (No. 2 overall, 2012) anchors the organization's more recent selections, with more help potentially on the way from the likes of prospects such as 2017's top overall pick, Royce Lewis.

ON THE RISE

Houston Astros (154.9 WAR)
George Springer (2011), Carlos Correa ('12) and Alex Bregman ('15) are all stars who helped the Astros capture their first World Series championship in 2017 and remain in their primes. Kyle Tucker ('15) and Forrest Whitley ('16) could lead the next wave in Houston.

Washington Nationals (150.4 WAR)
The franchise's late years in Montreal produced little, but its haul after reaching Washington helped set up a World Series title. Ryan Zimmerman (2005) became a franchise cornerstone, and Stephen Strasburg ('09), Bryce Harper ('10) and Anthony Rendon ('11) -- all top-six selections -- are stars in their primes. Harper and Rendon are now elsewhere, though, as is 2019 breakout performer Lucas Giolito.

Los Angeles Dodgers (122.2 WAR)
Clayton Kershaw (No. 7 in 2006) is their only top-14 pick in this time frame, and they knocked it out of the park. The lefty isn't done yet, and young teammates Walker Buehler, Gavin Lux and Corey Seager are ready to pick up the slack. This doesn't even take into account reigning NL MVP Cody Bellinger, who was a fourth-round steal.