10 Responses to “Biggest OBP – BA differentials in 2009”

1. DoubleDiamond Says:
   August 27th, 2009 at 5:47 pm

   Why do people insist on using the word "differential" when "difference" will suffice?

2. gerry Says:
   August 27th, 2009 at 7:26 pm

   Why do people insist on using "suffice" when "do" will do?

   To get back on-topic...Yank Robinson had a .134 delta - over a 10-year career. Check out his 1890 season, .434 - .229 = .205. See also Jack Crooks, .145 over an 8-year career.

3. JohnnyTwisto Says:
   August 27th, 2009 at 7:29 pm

   I'd say everyone ends up on this list for the same reason: they walk a lot (or get hit with lots of pitches).

   We need a good name for this. Isolated Power, of course, is SLG - BA. "Isolated On-Base" doesn't sound that good. "Isolated Walk Rate" isn't quite correct.

4. DavidRF Says:
   August 28th, 2009 at 12:21 am

   Actually, its not just walking a lot. Having a low batting average helps.

   OBP - AVG

   =(AB(H+BB+HBP) - H(AB+BB+HBP+SF))/(AB(AB+BB+HBP+SF))

   =((BB+HBP)(AB-H) - H(SF))/(AB(AB+BB+HBP+SF))

   =(1-AVG)(BB%+HBP%) - AVG*SF%

   (where in these rate percentages, SH's are removed from plate appearances)

   So, if my math is right, having a great walk rate and hit-by-pitch rate is much of the story, but having a low batting average helps.

5. tomepp Says:
   August 28th, 2009 at 12:34 am

   Gerry: Technically, you'd have to say, "the difference between OBP and BA", whereas you only have to say, "the OBP / BA differential" – it’s actually shorter. Also, 'difference' could refer to the definitional difference between how they are computed, while differential more clearly infers the difference in their numerical values.

   JohnnyTwisto: I'd say Walk Rate is a pretty good name for it. The problem is that their denominators are different (AB for BA, PA – SH for OBP), which means you're not really measuring the rate of anything. With Isolated Power, you're measuring the rate of extra bases earned per at-bat since both BA and SLG use AB as their denominators, but with WR you're over-deducting for hits.

   To clarify, consider the following simple example: A player gets 100 hits and 100 walks (no HBP or sacs) in 400 AB.

   OBP = 200 / 500 = .400
   BA = 100 / 400 = .250

   When you subtract the two, you get

   WR = .400 - .250 = .150

   Since the denominator of OBP is PA (actually PA – SH, but with no sacs we’ll simplify), the .250 we’re subtracting would represent .250 * 500 PA = 125 times on base. But that came from only 100 hits, so essentially we’re taking away credit for 25 of the player’s walks because he got 100 hits. If that same player had only gotten 50 hits and 100 walks in those same 400 AB:

   OBP = 150 / 500 = .300
   BA = 50 / 400 = .125
   WR = .300 - .125 = .175

   So his WR goes up .025 because he’s a lousy hitter otherwise. In this case, the .125 we’re subtracting would represent .125 * 500 PA = 62.5 times on base. Since that came from only 50 hits, we’re essentially taking away credit for only 12.5 of the player’s walks instead of 25.

   The fact that sacrifice flies are also counted in the denominator of OBP but not BA makes it possible for someone with few or no walks and HBP but a significant number of SFs to have an OBP lower than his BA, and thus a negative WR.

   While "WR" is easily computed because BA and OBP are often already calculated, a more reliable way to measure it is simply,

   (H+BB+HBP) / PA

   or you could use PA – SH (the same as OBP) in the denominator if you prefer. This would calculate the true walk rate, which is what I think we were getting at in the first place.

6. tomepp Says:
   August 28th, 2009 at 12:39 am

   DavisRF is right, as my example illustrates. I was composing my response before David's was posted, so I didn't see it until after posting mine. As my examle illustrates, a lower BA means you're "taking away credit" for fewer walks because of the over-valuation of the hits in BA.

7. nutbunnies Says:
   August 28th, 2009 at 5:40 am

   "We need a good name for this. Isolated Power, of course, is SLG – BA. “Isolated On-Base” doesn’t sound that good. “Isolated Walk Rate” isn’t quite correct."

   How the hell have you heard of IsoP but not IsoD (Isolated Discipline, which is what this is)???

8. bravesfan513 Says:
   August 28th, 2009 at 7:07 am

   The biggest career difference between OBP and BA is by Max Bishop, who hit .271 but had a .423 career OBP, a 152 point difference. Next are Gene Tenace (147) and Barry Bonds (146).

   The smallest difference all time is by Pop Snyder, whose .254 OBP was just 19 points higher than his .235 BA.He walke 83 times in his career, or once every 45 PAs.

9. Andy Says:
   August 28th, 2009 at 8:06 am

   My point in writing the post was to point out guys like Swisher, Pena, Thome, Cust, and Uggla who have low batting averages but pretty high OBP this year. Most baseball stats folks will not overlook something like, but there are plenty of fans out there who still only go by batting average, and there are a select number of players who still have very high OBP despite low BA.

10. Lazy Links Says:
    September 15th, 2009 at 10:54 am

    [...] Reference lists the players with the biggest discrepancies between their batting average and on base [...]