Power and Patience (Part IV of a Study)

We saw in Part Three that the R^2 between OBP and ISO for the annual average of each from 1901-2013 is .373. To find out the correlation between OBP and ISO at the individual level, I set the leaders page to multiple seasons 1901-2013, split the seasons, and set the minimum PA to 400, then exported the 16,001 results to Open Office Calc.

(Yes, sixteen thousand and one. You can find anything with FanGraphs! Well, anything that has to do with baseball. Meanwhile, Open Office operating on Windows 7 decides it’s tired the moment you ask it to sum seven cells. At least it gets there in the end.)

The result was .201, so we’re looking at even less of a correlation in a much larger sample compared to the league-wide view. Are there periods where the correlation is higher?

Recall from Part Two that from 1994-2013 the R^2 for the league numbers was .583. Using individual player lines (400+ PA) from those seasons increases our sample size from 20 to 4107 (again splitting seasons). This gives us an R^2 of .232. That’s a little higher than .201, but not very much so.

All in all, it’s not the most surprising thing. On-base percentage and isolated power, mathematically, basically have nothing in common other than at-bats in the denominator. Given that, any correlation between them at all (and there is some) suggests that it either helps players hit for power to be an on-base threat, or vice versa. Not that one is necessary for the other, but there’s something to it. And throughout history, as we saw in Part One, a majority of players are either good at both aspects of hitting, or neither.

In fact, it’s the exceptions to that rule that triggered this whole series, those higher-OBP, lower-ISO players. Again from part one, there were 12 19th century, 21 pre-1961 20th century, and 3 post-1961 20th-21st century players with a career OBP over .400 and ISO below .200.

Much of this can probably be attributed to that consistency OBP has had historically relative to ISO that we observed a couple weeks ago. Continuing with the somewhat arbitrary 1961 expansion era cutoff, from 1961-present, 168 players with 3000 PA have an ISO over .200 and 18 have an OBP over .400; from 1901-60, it was 43 with the ISO over .200 and 31 with the OBP over .400. The .200+ ISO’s are split 80-20% and the .400+ OBP’s are split about 60-40%. The latter is the much smaller gap, as we’d expect. (Some players whose careers straddled 1961 are double-counted, but you get the basic idea.)

But let’s see if we can trace the dynamics that brought us to this point. What follows is basically part of part one in a part three format (part). In other words, we’re going to look at select seasons, and in those seasons, compare the number of players above and below the average OBP and ISO. Unfortunately, it’s hard to park-adjust those numbers, so a player just above the average ISO at Coors and a player just below it at Safeco are probably in each other’s proper place. But that’s a minor thing.

After the league-wide non-pitcher OBP and ISO are listed, you’re going to see what might look like the results of monkeys trying to write Hamlet. But “++” refers to the number of players with above-average OBP and ISO; “+-” means above-average OBP, below-average ISO; “-+” means below-average OBP and above-average ISO; and “- -” means, obviously, below-average OBP and ISO. The years were picked for various reasons, including an attempt at spreading them out chronologically. Notes are sparse as the percentages are the main thing to notice.

1901: .330 OBP, .091 ISO. Qualified for batting title: 121. 35% ++, 25% +-, 12% -+, 28% – –

1908: .295 OBP, .069 ISO. Qualified for batting title: 127. 41% ++, 23% +-, 8% -+, 28% – –

The sum of OBP and ISO was its lowest ever in 1908.

1921: .346 OBP, .117 ISO. Qualified for batting title: 119. 42% ++, 24% +-, 8% -+, 26% – –

Baseball rises from the dead ball era. Still relatively few players are hitting for power while not getting on base as much.

1930: .356 OBP, .146 ISO. Qualified for batting title: 122. 45% ++, 23% +-, 3% -+, 29% – –

The best pre-WWII season for OBP and ISO. Almost nobody was about average at hitting for power while not as good at reaching base. Two-thirds of qualifiers had an above-average OBP vs. fewer than half with an above-average ISO.

1943: .327 OBP, .096 ISO. Qualified for batting title: 106. 41% ++, 24% +-, 10% -+, 25% – –

World War II, during which OBPs stayed near the average but ISOs tanked. That would not necessarily appear in these numbers, because the players in this segment are categorized vs. each year’s average.

1953: .342 OBP, .140 ISO. Qualified for batting title: 88. 44% ++, 22% +-, 14% -+, 20% – –

The first year where sISO exceeded OBP was easily the lowest so far in terms of players below average in both OBP and ISO. (Note: So few players qualified on account of the Korean War.)

1969: .330 OBP, .127 ISO. Qualified for batting title: 121. 45% ++, 17% +-, 14% -+, 23% – –

1983: .330 OBP, .131 ISO. Qualified for batting title: 133. 43% ++, 16% +-, 17% -+, 25% – –

1969 and 1983 were picked because of their historically average league-wide numbers for both OBP and ISO. The percentages for each of the four categories are about equal in both seasons.

2000: .351 OBP, .171 ISO. Qualified for batting title: 165. 39% ++, 16% +-, 15% -+, 29% – –

The sum of OBP and ISO was its highest ever in 2000.

2011: .325 OBP, .147 ISO. Qualified for batting title: 145. 50% ++, 17% +-, 12% -+, 21% – –

2012: .324 OBP, .154 ISO. Qualified for batting title: 144. 44% ++, 24% +-, 14% -+, 18% – –

2013: .323 OBP, .146 ISO. Qualified for batting title: 140. 45% ++, 24% +-, 17% -+, 14% – –

Originally, this part ended with just 2013, but that showed an abnormally low “- -” percentage, so now 2011-13 are all listed. From 2011 to 2012, the split groups (above-average at 1 of the 2 statistics, “+-” or “-+”) increased sharply while the number of generally good and generally bad hitters decreased. From 2012 to 2013, there was almost no change in qualifiers based on OBP (the “++” and “+-” groups). Among those with below-average OBPs, the number with above-average power increased as the number with below-average power decreased. Most significantly, 2011-13 has produced an overall drop in players who are below average at both.

I don’t want to draw too many conclusions from this set of 12 out of 113 seasons. But a few more things come up besides the recent decline in players below average in both OBP and ISO.

Regarding “++” Players

Unsurprisingly, limiting the samples to qualifiers consistently shows a plurality of players to be good at both the OBP and ISO things.

Regarding “- -” Players 

Essentially, until 2012, this group was always at least 1/5 of qualifiers, and usually it was 1/4 or more. The last couple years have seen a decline here. Is it a trend to keep an eye on in the future (along with the league-wide OBP slump from Part 3)?

Regarding “++” and “- -” Players

Meanwhile, the majority of players will be above average at both getting on base or hitting for power, or below average at both. The sum of those percentages is just about 60% at minimum each year. Of the ten seasons above, the lowest sum is actually from 2013, mostly on account of the 14% of players who were below average at both.

This also means that it’s a minority of players who “specialize” in one or the other.

Regarding “+-” vs. “-+” Players

The “-+” players, those with below-average OBPs and above-average ISOs, show the best-defined trends of any of the four categorizations. In general, before 1953, when OBP was always “easier” to be good at than ISO (via OBP vs. sISO as seen in Parts 2 and 3), you saw fewer ISO-only players than you see today. Either they were less valuable because power was less a part of the game and of the leagues’ offenses, or they were less common since it was harder to exceed the league average.

The number of OBP-only players is more complicated, because they too were more common in the pre-1953 days. But they have jumped in the last two years from 1/6 of qualifiers from ’69-’11 to 1/4 of qualifiers in 2012 and 2013. Overall, the recent decline in “- -” players has come at the expense of “+-” players. This can also be interpreted as indicating that players are becoming better at reaching base while remaining stagnant at hitting for power (important distinction: that’s compared to the annual averages, not compared to the historical average; as we saw last week, OBP is in a historical decline at the league level).


The key takeaway for all of this is that there are always going to be more players who are above-average in both OBP and ISO or below average in both. Even if the correlations between OBP and ISO on the individual level aren’t overly high, clearly more players are good at both or at neither.

This isn’t just on account of players with enough PA to qualify for the league leaders being better hitters in general, because while the number of players above-average in both who qualify is always a plurality, it’s almost never a majority. It takes a number of players who are below-average at both to create a majority in any given year.

In terms of OBP-only players and ISO-only players, the former have almost always outnumbered the latter. This is sufficiently explained in that reaching base is often key to being a good hitter, while hitting for power is optional. (That’s why OPS has lost favor, because it actually favors slugging over OBP.) Even when batting average was the metric of choice throughout baseball, those who got the plate appearances have, in general, always been good at getting on base, but not necessarily at hitting for power.

Next week this series concludes by looking at the careers of some selected individual players. The most interesting ones will be the either-or players, with a significantly better OBP or ISO. We won’t look much at players like Babe Ruth or Bill Bergen, but instead players like Matt Williams or Wade Boggs. Stay tuned.

hscer (pronounced h-s-seer) is also the Curator of MLB quizzes at Sporcle.com. You can join Dan Szymborski in following hscer on Twitter.

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