Brief Sabermetric Primer: IsoP

by redsoxstatscom on Jan 25, 2010 9:40 AM EST

For today's sabermetric primer I decided to take a look at IsoP, or Isolated Power.

Isolated Power can trace its roots in one form or another back to Branch Rickey and Al Roth in the 1950’s. The metric measures a batters power based on how many, and what type of, extra-base hits a player has amassed. Whereas slugging percentage counts all hits including singles, IsoP deals with only doubles, triples and home runs.

The most common formula for IsoP is (SLG - AVG), which is the same as (2B + 3B*2 + HR*3) / AB. However, when Baseball Prospectus uses IsoP for their PECOTA projections they give equal weight to doubles and triples since "extending a double into a triple is generally an indicator of speed, rather than additional power."

I agree with Baseball Prospectus’ reasoning so on redsoxstats.com the final formula I use is: (2B + 3B + HR*3) / AB.

In 2009 the American League IsoP was .156 with the National League checking in at .143. Albert Pujols led the majors with his .329 mark while running away from Carlos Pena who finished second at .306. Luis Castillo checked in with the lowest IsoP of qualified hitters at .037.

Jason Bay was 11th in the majors at .256, Kevin Youkilis 20th at .240 and JD Drew 25th at .235.

When you think about power and the Red Sox one name comes to mind, David Ortiz. Since joining the Red Sox in 2003, Ortiz has a collective .287 IsoP. However, heading into his age 34 season, Ortiz’s IsoP is on a 3-year slide coming off of his magical 2006 season.

It should be noted that Ortiz did have an IsoP over .250 in each of the final four months of last season after not cracking .100 in April or May. Hopefully consistency returns in 2010 as the Red Sox will need his bat, but banking on an aging slugger in a downward spiral is risky.

The top IsoP sluggers in the Red Sox minor league system last season were Ryan Lavarnway, Josh Reddick, Tim Federowicz, Anthony Rizzo, Jon Still, Christopher McGuiness, and Ryan Westmoreland.

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Comments

wow

I like this stat!! I agree with the 3b’s also counting just as much as doubles.

by Jason A on Jan 25, 2010 12:29 PM EST reply actions

not sure I like this stat

It’s probably most useful just to see changes over time in one batter.

I don’t agree that it truly isolates on measuring ‘power’ because it includes all At Bats – thus it treats all non-Xtra-Base Hits equivalently. This is merging two negatives together in the divisor: 1) Weakness (lack of power) and 2) inability to hit the ball at all.

A better measure of ‘power’ that isolates on just that is to divide the extra base hits (or a weighted sum as used above) by the total number of hits (including singles). That truly isolates on “IF he hits the ball, how powerful does he hit it.” and keeps the “Can he even hit the ball?” question completely separate (and properly answered already by “Batting Average”).

by mmmmm on Jan 25, 2010 12:57 PM EST reply actions

Iso

I see your point here. Perhaps, ISO is better seen as a rough estimate for how much value a player provides with his power rather than simply how much power he has when he actually hits the ball.

by metric on Jan 25, 2010 4:42 PM EST up reply actions

THAT I could accept. But it needs a better name then.

by mmmmm on Jan 25, 2010 4:52 PM EST up reply actions

interesting

Jason Bay was 11th in the majors. 11th. Much better than Youk or Drew. And the Sox didn’t want him. Wow. If he continues to produce and does not blow out his knee or shoulder in the next 3 years, I will be livid. Of course this depends upon how well the Sox do without him, but if they struggle for production this year and miss the playoffs…………

by Scoop1981 on Jan 25, 2010 1:10 PM EST reply actions

Don't confuse

ISO with quality. Iso only indicates what it indicates-how much of a player’s hits are of the extrabase variety. Nample how much power a player has above and beyond slugging. It does not indicate anything that is not obvious about Bay-he largely gets on due to exta base hits and BBs. Lat year Carlos Pena almost had a historic year in that he came within 2 hits of having more HRs than singles. That is not necessarily a good thing! Youkilis has been a clearly better offensive player than Bay over the last 2 years.

by Buzzy on Jan 25, 2010 1:20 PM EST up reply actions

+1

Don’t confuse ISO with quality.

Quoted for emphasis.

by mmmmm on Jan 25, 2010 2:11 PM EST up reply actions

+1

Players like Pena and (to a lesser extent) ar rewarded in terms of IsoP by having a crappy average.

Manny ain't the only bad man.

by tommy.otm on Jan 25, 2010 10:21 PM EST up reply actions

Yup.

IsoP is more about how a player contributes; not whether he contributes.

"Ninety percent [of my salary] I'll spend on good times, women, and Irish whiskey. The other ten percent I'll probably waste."
-Tug McGraw

by BTLove on Jan 26, 2010 1:46 AM EST up reply actions 1 recs

Rec'd

Important.

Galactus does as he pleases. Because Galactus is drunk.

I have a five-tool player in my pants.

by Bloggy on Jan 26, 2010 6:35 AM EST up reply actions

ISO actually shows the main problem with Bay

Which is that while he has such huge power, he doesn’t put the bat on the ball enough. ISO measures only power.

USG

by Ben Buchanan on Jan 25, 2010 1:49 PM EST up reply actions

tinypic.com/2s99fz4 here is a strikeout rate / isolated power scatter plot. look at albert, ha. bay is in the cruz, dunn, howard, branyan area code.

by redsoxstatscom on Jan 25, 2010 2:39 PM EST up reply actions

Ugh this is making me like this stat even less

What are we supposed to learn from this plot?

The only good thing I can see is it (IsoP v SO%) divides out at-bats.

But what does it really tell us about anybody? I’m seeing good hitters clumped near crappy ones.

by mmmmm on Jan 25, 2010 4:23 PM EST up reply actions

Iso tells you power. That's it. How hard does this guy hit it.

It’s usually best in evaluating prospects or young guys, really, because it keeps you from undervaluing a guy who’s got immense raw power but can’t necessarily connect. For instance, someone who has a line of .200/.280/.400 looks like he’s got the power of Ellsbury, but actually probably has big-HR potential if he can get the bat on the ball more.

USG

by Ben Buchanan on Jan 25, 2010 4:42 PM EST up reply actions

No - IsoP tells you how much power he has per At-Bat

because it is ratio’ed against At-Bats. That is not the same as how much power he has.

Its a fine distinction, but real. Let’s look at your specific usage example, with a couple of hypothetical prospects:

Player A:
AB: 100
Hits: 36
2B: 8
3B: 0
HR: 3

Player B:
AB: 100
Hits: 11
2B: 8
3B: 0
HR: 3

Both have an IsoP of .170. Do you think that both hitters have the same ‘power’?

In the first case, only 11 of 36 of Player A’s hits were for extra bases. In the second case, 100% went for extra bases.

Player B is clearly a more powerful hitter. He just also sucks (currently) as a hitter, period. If he learns to hit, then it is logical to assume that he will keep a power advantage over player A. IF.

If the goal is to isolate and amplify their actual power at hitting the ball separate of their ability to HIT the ball (per your example) then it would be better to divide by the number of Hits, not ABs.

by mmmmm on Jan 25, 2010 5:06 PM EST up reply actions

Good point.

USG

by Ben Buchanan on Jan 25, 2010 6:52 PM EST up reply actions

OK, Bay sucks

Is this an official Red Sox site? Does anybody here except me believe the Red Sox management is capable of making a mistake? Problems with Bay? Ellsbury a mediocre to poor outfielder? It is plainly obvious that the Red Sox front office is just smarter than everybody.

by Scoop1981 on Jan 25, 2010 6:41 PM EST up reply actions

Nobody is saying Bay sucks.

Just that the contract he received would be a big risk, and that his high Iso isn’t a good reason to say they should’ve resigned him.

Ellsbury being a mediocre center fielder (a notable distinction) held up last year both in numbers and in observations. If he improves his reads, he’ll be great, but bad reads kill speed.

And we don’t think the front office is infallible at all. Lowell and Lugo are proof enough of that. Many of us disagree with many of the decisions they make—though quite clearly they ARE smarter than just about everybody given how often they get it right and how much they pay expert analysts, scouts, etc. in order to GET everything right.

USG

by Ben Buchanan on Jan 25, 2010 6:55 PM EST up reply actions

you'll note if you go back

that most people on here weren’t in favor of giving Bay the contract he wanted going much farther back in the season.

by wolf9309 on Jan 27, 2010 9:30 AM EST up reply actions

how far back?

May – back up the brinks truck?
August – release him?

The point is that Bay as been a solid producer, and a HEALTHY one at that, for several big league seasons. I’m sorry, as a fan, I would simply prefer Bay over Cameron and I don’t believe the $$ savings will enable the Sox to make a move they would otherwise not be able to make. If Theo and the team come out and say they have allocated the Bay money to Alex Gonzalez or another top player, I will feel differently.

by Scoop1981 on Jan 27, 2010 10:01 AM EST up reply actions

perhaps I misunderstood you

it sounded like you were saying that the people here are parroting the front office and saying that the front office is right after they have made there decisions, whereas a lot of people here were saying not to give him the contract before the front office (at least publicly) closed that door.

I have severe problems with your assertion that Alex Gonzalez is a top player- he is a very good defensive player (though declining) with a consistent black hole at the plate. I believe Scutaro will be an improvement over him by quite a bit. I also think it’s fairly clear that the “Bay money” was specifically allocated to Lackey who, whatever you think of the deal, is certainly a top player at this point. They would not have spent that money on him if they had been paying Bay the amount he got- plus the Bay contract is more money per year over a long period of time, so Cameron leaves us flexibility in the future to bring in younger players.

Cameron is certainly not the offensive force that Bay was, and our outfield in general is probably not as strong as it was in 2009, however the impressive defensive improvements should help mitigate the loss of his offensive output. The rest of the team besides the outfield is simply miles ahead of where it was in 2009.

by wolf9309 on Jan 27, 2010 10:27 AM EST up reply actions

He meant Adrian.

But more importantly, it’s not all about what the Sox do this year. It’s that they’d be locked into what will most likely be an albatross contract halfway through as Bay will likely decline with age and become a DH who can’t kill the fastball like he used to.

USG

by Ben Buchanan on Jan 27, 2010 10:35 AM EST up reply actions