WNBA Most Improved Player award race: Putting Skylar Diggins' dramatic second-year improvement in perspective

After noticing a few NBA fans using Tulsa Shock guard Skylar Diggins as an example of a player who overcame a poor rookie year to become a productive player, I wondered whether that was happening because they were truly that tuned into the WNBA or there just wasn't a better example on the men's side.

Searching through all of NBA history for the biggest first to second year improvements would take some time even with Basketball-Reference's player season finder but Diggins made it pretty easy by simply posting an outstanding PER pf 21.6: as it turns out, only 33 NBA players ever have posted a PER of 21.6 or higher in their second season. And if you look at the list, it's a group of All-Stars, Hall of Famers, and young current guys who are still establishing themselves in the league. Not surprisingly, not one of them had a rookie year anywhere near as poor as Diggins (9.8 PER) - going from as bad as Diggins was in her rookie year to as good as she's been this year is almost unheard of in pro basketball, men's or women's.

How much has Diggins improved?

Basketball-Reference doesn't (yet) allow us to search its database for the WNBA in the same way, but you can look through the list of past WNBA Most Improved Player award winners and see that Diggins has a chance to finish this season with a larger year-to-year increase in PER (+11.8) than any MIP winner in the history of the WNBA. She'll have to finish her season strong to catch up to 2011 winner Kia Vaughn - one of the most impressive improvements in recent memory - but it's pretty clear that she is doing something quite remarkable.

Top single-year increases in PER among past WNBA Most Improved Player award winners.

It's worth noting that we can't take the next step and say that Diggins has made one of the biggest improvements ever - as noted above, the list of award winners is not necessarily a record of the biggest year-to-year increases in PER because voters obviously use other factors in making selections. But mining the data we can easily sift through at Basketball-Reference really does help to put Diggins' improvement this season in perspective: she has taken a leap that, if not unprecedented, is at least rare and worthy of honoring for the historical record. Tari Phillips made a similar second-year leap, but Diggins may have made a uniquely large second-year leap for a guard in pro basketball history in terms of how strong her second-year PER is.

Of course, earlier this season when discussing the Most Improved Player Award, I mentioned that as good as Diggins had been I was biased against second-year players because they're theoretically supposed to improve and haven't yet established a clear baseline for expectations (no, 34 games is really not enough to establish expectations). Yet having looked over the current season's year-to-year improvements by Valuable Contributions Ratio (VCR), I can say with confidence that nobody has made an improvement anywhere near the leap that Diggins has made even if you include players who changed situations or saw their minutes drop.

Why has Diggins improved?

I used PER as a catch-all statistic because it's publicly available and a number people are familiar with, but the specifics of how Diggins has improved are just as impressive on their own.

Skylar Diggins' career statistics (via Basketball-Reference).

Obviously, Diggins' scoring has improved dramatically this season but (as usual) what's more interesting is the leap in scoring efficiency (TS%).

One of Diggins' biggest struggles in her first year was having the strength to get into the paint and finish through contact - it was obvious from watching and one of the things mentioned about her offseason program. This year, with added strength, Diggins is getting to the free throw line more often (see the free throw rate column) and shooting a lower percentage of her shots from three point range (three point rate). That shift in shot selection - getting more shots inside the three point line - is particularly important for a player like Diggins who is only a 25.8% three point shooter to begin with.

Looking further down that table though, you also see that she's turning the ball over at a lot lower rate. And one reason for that could be the way the Shock are playing this season: without Liz Cambage around in the post, the Shock are just running pick-and-roll after pick-and-roll to Diggins and backcourt mate Odyssey Sims and just daring people to stop it. With Diggins in more of a feature scorer's role than a distributor's role this season - and Sims sharing some of that ball handling pressure - she's able to play to her scoring strength a lot more easily.

How much more can Diggins improve?

Despite the gains this season, Diggins still has plenty more room for improvement and a large part of that is on the defensive end where neither the numbers nor the film are very pretty (she has been clearly targeted by opposing teams in late-game situations this season). But another part of her potential room for improvement is found within that balance of being a scorer and distributor, particularly given the Shock's personnel.

Diggins and Sims are by no means the same player, but they're similar in that their numbers put them firmly in more of a small scoring guard than pure distributor category - that's not a bad thing, but it'll be interesting to see how that plays out for the Shock down the road. Diggins is a much more efficient ball handler this year than she was last year due to the falling turnover rate - her pure point rating of 1.77 is a significant improvement on last season's -1.18 rating - but she's also neither a particularly efficient scorer or distributor at this point.

Diggins' scoring efficiency will always be somewhat low as long as she shoots below 30% from the three point line while her efficiency as a distributor will be hampered as long as she's a featured scorer who draws the bulk of defensive attention from opponents. Again, that's not necessarily a bad thing, but if she's going to entrench herself among the league's elite at the (combo) guard position, becoming more efficient on one front or the other is probably the path forward.

And if her improvement from her rookie to second year is any indication, we probably should expect her to continue working on her game and show us something new next season.

I'll gladly put those MIP numbers together if you really want to see them, but I've put the top three contenders into the poll below for you to weigh in on.