Are Ted Williams’ Hitting Philosophies Still Relevant Based on the Data?

In hindsight, it’s unfortunate that Ted Williams philosophies on hitting took so long to become universally accepted. His thoughts on batting were clearly ahead of his time and it has only been in the past few years that the more prevalent “swing down” views have largely exited the baseball community.

In his book, The Science of Hitting, Williams suggested an upward swing path that aligns the bat path and pitch path for a better chance of contact – about 5 degrees for a fastball and 10-to-15 degrees for a curveball. This research note is not about the total amount of loft in the swing today — everyone knows that swing loft is greater now than in Williams’ day. However, there are some very interesting findings in the data in terms of whether players are utilizing consistent amounts of swing loft for different pitch locations, which is implied in Williams’ book.

One observation that seems to hold in many sports is that the best performers are typically out in front of the popular views of the day in terms of changing mechanics for the better. However, as we will see in the data, this does not necessarily mean that these superior mechanics are being understood and directed by conscious understanding.

It turns out that there is a very important element that wasn’t considered by Williams in his book which the data shows the best hitters are “considering” — the amount of Vertical Bat Angle (VBA) in the swing. VBA can be defined as the amount of vertical swing tilt as viewed from the center field camera. The swings in Williams’ day as well as the illustrations in his book clearly have much less VBA than today’s hitters. While there is no broad data on VBA, a study of minor league hitters by David Fortenbaugh in 2011 showed the following averages of VBA at contact:

There is evidence which suggests that VBA goes well beyond player “style” and is more of a core swing mechanic that is associated with higher quality contact as well as superior levels of performance. Here is a chart showing VBA by playing level.

A recent post of mine here examines whether players should try to hit with backspin. What is interesting about VBA is that it appears to play a very important role in reducing backspin, leading to more “square” contact. As you can see from the following illustration, as VBA increases, the chance of hitting the ball with pure backspin decreases while the chance of sidespin increases. In essence, the player on the right is trading the more unfavorable vertical variability for more performance-friendly horizontal variability.

There are several different angles which can be used to describe swing path. I’ll focus on three of those angles — Explicit Swing Loft (the upward or downward angle of the swing path from catcher to pitcher), Horizontal Bat Angle (HBA) — the angle of the bat as it travels along the three-dimensional swing path, and VBA as described above. The angle that Williams describes in his book is the same as Explicit Swing Loft. Many in the industry refer to this as “Attack Angle,” but this is a very confusing term as it does not consider very important elements of loft discussed below.

Based on the data, are the best hitters using consistent Explicit Swing Loft approximating the path of the incoming pitch as recommend by Williams (holding pitch type constant)?  The answer to that question is very interesting. In fact, to fully understand what the best hitters are doing, it is important to understand how adding VBA to the mix impacts the total amount of bat loft.  If VBA is assumed to be zero (illustrative purposes only), then the total amount of bat loft is equal to the angle of the Explicit Swing Loft – regardless of the whether the ball is hit early (positive HBA) or late (negative HBA, left graphic).

Once VBA is considered, however, there is clearly an impact on loft in terms of early or late contact – even if the amount of Explicit Swing Loft is neutral (right graphic). Thus there are two very different types of bat loft.

Mathematically, the amount of loft coming solely from the compound angle of VBA and HBA at ball contact can be defined as follows (it’s not pretty but you can copy into Excel and play with different angle combinations to see the loft impact):

sinˉ¹ (sin(HBA*(PI()/180))*sin(VBA*(PI()/180))))*(180/PI())

So the total amount of loft of the bat at contact is influenced by all three angles – Explicit Swing Loft, VBA, and HBA. For example, if (for a low inside pitch) VBA is 48 and HBA is 23, then “square” contact off of that compound angle would result in loft of 17 before considering the influence of Explicit Swing Loft. VBA will almost always be in only one direction and is presented here as a positive value. HBA can be positive or negative depending on swing timing.

What the data shows is that the best hitters, in an apparent effort to hit with more launch angle consistency, are “considering” the loft implications from early or late contact and adjusting the amount of Explicit Swing Loft accordingly. In other words, for a low inside pitch, they are using extremely low levels of Explicit Swing Loft (close to zero) while using much higher levels of Explicit Swing Loft for outside pitches where the loft impact from the later contact is often negative.

Let’s take a look at Joey Votto’s angles for two pitch locations derived from video and Statcast data (positive HBA values are to the pull side). Statcast values for launch angle and horizontal ball direction represent averages taken over the 2015-2018 seasons (the derivation of HBA from horizontal ball direction and VBA is not shown here):

Low/Inside High/Outside
Vertical Bat Angle 48 33
Horizontal Bat Angle 23 -10
Loft from Early/Late Contact (VBA/HBA)* 17 -5
Explicit Swing Loft / aka Attack Angle* -3 19
Actual Ball Loft for Pitch Location 14 14

*Assumes “square” contact. Limited to well-hit balls (>90 mph, 0-45 degrees LA).

Clearly, the best hitters are not using a consistent upward-sloping swing path as recommended by Williams based on the data. Notwithstanding the likelihood that many players could benefit from increased levels of VBA, the loft coming from the compound angle of the contact point is largely outside the hitter’s control and is primarily a reaction to the pitch location – more VBA and HBA as pitches get more inside and lower. The data suggests that the best hitters are actively using Explicit Swing Loft as a counter-balance in order to maintain more consistent total loft for different pitch locations, as we see in Votto’s case above.

In terms of the statement in his book that hitters should utilize differently lofted swings for different pitch types (i.e. fastball vs curveball), the data for Qualified Hitters from 2016-2018 suggests they do not. The average launch angles of well-hit balls off low/middle pitches towards the middle of the field (to minimize loft impact from an early/late contact point) were almost identical at 17 degrees for both pitch types.

It is really quite remarkable that hitters are using very different angle combinations depending on the pitch location in order to produce more consistent total loft at contact. Even more interesting in my view is: How did these players come to “understand” these two very different types of loft? Given the information on swing path in the public domain, it is virtually impossible that this “knowledge” has come about as a result of conscious understanding. The subconscious “hitter brain” is likely infinitely smarter than the conscious side and has come to understand the complexities of swing path without hitters fully understanding exactly what is happening. This leads to a very logical but exciting question of what other similar discoveries might be hiding in the subconscious that could be unlocked for significant value. It would also seem to reason that we don’t necessarily have to understand fully what is happening in the subconscious in order to benefit from it.

Although the advice to “swing with a consistent path” seems perfectly logical on the surface, it is a complete misnomer based on the data of what the best hitters are actually doing. Other seemingly “good advice” such as “keep the barrel in the zone” is another popular hitting cue that does not hold up to the data. I’ll examine that in a future piece.

D.K. Willardson enjoys research connecting data, mechanics, and technology and is the author of Quantitative Hitting: Surprising Discoveries of the Game’s Best Hitters. He is also the developer of the Quant Tee and SwingGraphs.

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This was really interesting. Looking at the chart of VBA at each level, I’m guessing that in youth baseball, the VBA is lower simply because the swing plane is literally closer to the ground since the hitters are so small. Then as the players grow, there is a relatively rapid increase in VBA until they approach physical maturity. From there the increase in VBA is more gradual, and you see that the players with more optimal VBAs are the ones who advance to each higher level (or is it the players who advance are the ones with more optimal VBA?… Read more »


Good article. Williams wasn’t really on the vertical angle thing, he had an upward swing but it was flat and rotational. Aaron was like this too. This probably was also a function of the K zone. The strike zone was higher back then, and the steep barrel swing is not good against high pitches but good against low pitches. Williams had a good eye and reputation with the umps, he simply didn’t bother with the low pitch and waited for a belt high pitch to crush. Hitters of the 00s and 2010s couldn’t afford to do that because the zone… Read more »