# The Hardball Times Fantasy

## The control hitters have over everything

by Derek Carty
July 29, 2009

A couple weeks ago, I wrote an article titled "The control hitters have over LD%," examining why it's a bad idea to use single-year line drive rates in any discussion of a hitter's underlying skills. Afterward, I received an e-mail from a reader who wanted me to go a step further:
Hi Derek,
I really enjoyed your post on the stability of LD% over time. It was very helpful to have the GB% correlation (.65) as a comparison. I want to encourage you to do a post at some point on the stability of a variety of common conventional and sabermetric stats; I fully understand the concept of looking for stable, repeatable skills but I have little idea what is stable and repeatable! For example, how stable is a player's walk rate? Strikeout rate? HR/FB rate?

Just a table of 20 of these stats would be really cool for perspective.

With that, here we go...

### The results

As I said last time, this is far, far from a comprehensive study. For comparative purposes, though, it can be quite useful. Anyway, I looked at all hitters from 2004 through 2008 who amassed at least 350 at-bats in adjacent seasons (and played on the same team both years, to eliminate some park-to-park biases). What you're seeing is the R-squared results for each stat, which essentially tells us how much of the variation in Year 2 can be explained by the Year 1 figure.

```+---------------------------+------+
| STAT                      | R2   |
+---------------------------+------+
| Batting Average           | 0.18 |
| On-Base Percentage        | 0.36 |
| Slugging Percentage       | 0.37 |
| OPS                       | 0.35 |
| ISO Power                 | 0.52 |
| ISO Discipline            | 0.60 |
| Batting Average with RISP | 0.06 |
+---------------------------+------+
| Contact (K) Rate          | 0.76 |
| Walk Rate                 | 0.61 |
| HBP Rate                  | 0.37 |
| Pitches per PA            | 0.61 |
+---------------------------+------+
| BABIP                     | 0.15 |
| 1B per BIP                | 0.21 |
| 2B per BIP                | 0.16 |
| 3B per BIP                | 0.26 |
| AB/HR                     | 0.42 |
| HR/FB                     | 0.59 |
| GIDP Rate                 | 0.13 |
+---------------------------+------+
| LD%                       | 0.09 |
| GB%                       | 0.60 |
| OF FB%                    | 0.52 |
| IF FB%                    | 0.43 |
+---------------------------+------+
| SBO%                      | 0.33 |
| SBA%                      | 0.80 |
| SB%                       | 0.10 |
+---------------------------+------+```

### Quick takeaways

As we always stress here at THT Fantasy, stats like batting average and BABIP are poor indicators of a player's actual skill. It's much better to focus on component skills like contact rate, which is one of the most stable stats around. Home runs are relatively stable, which might surprise some but really shouldn'tâ€”after all, Juan Pierre isn't going to start posting 30-home run seasons, nor is Ryan Howard going to hit only five home runs.

As we saw last time, line drive rate is very unstable, while the other batted ball stats are much more stable. And for those who like to blame hitters for being "unclutch" with runners in scoring position (I hear far too much of this from fellow Mets fans), check out no. 7 on the list.

### Quick glossary

EDIT: I'm adding this late per request. Sorry for some things being a little unclear to begin with.

ISO Power: SLG-AVG
ISO Discipline: OBP-AVG
Contact (K) Rate: Contact rate on a per AB basis (not a per pitch basis). Calculated as (AB-K)/AB
HR/FB: Home runs per outfield fly ball
GIDP Rate: GIDP/BIP
LD%: Line drives as a percentage of all non-bunt balls in play
GB%: Groundballs as a percentage of all non-bunt balls in play
OF FB%: Outfield flies as a percentage of all non-bunt balls in play
IF FB%: Infield flies as a percentage of all non-bunt balls in play
SBO%: Stolen base opportunity rate. The percentage of times a hitter reaches first and thus is in position to attempt a steal. Calculated as (1B+BB+HBP-IBB)/TPA.
SBA%: Stolen base attempt rate. The percentage of times a hitter attempts a steal given that he is on first base. Calculated as (SB+CS)/(1B+BB+HBP-IBB).
SB%: Stolen base success rate. The percentage of times a hitter is successful on a steal attempt. Calculated as SB/(SB+CS).

### Concluding thoughts

That's all for today. Any questions, feel free to comment or e-mail me!

Derek Carty, 23, has also been published by NBC's Rotoworld, Sports Illustrated, FOX Sports, and USA Today. This season, he'll be contributing to FanDuel and will be linking to all of his work at DerekCarty.com. In his three years competing in expert leagues, he has won 2 titles with 4 top three finishes, including a LABR NL title in 2009, making him the youngest person to ever win a major expert league title. Derek is a proud graduate of the MLB Scouting Bureau's Scout Development Program and is a firm believer in the importance of combining stats and scouting. He welcomes questions via e-mail, Facebook, or Twitter.