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BPA -- Measuring Offensive Performance

By Bill Gilbert (73623.2146@compuserve.com or billgilbert@postoffice.worldnet.att.net )

Numerous methods have been devised to measure offensive performance. The most common are batting average, on-base average and slugging average. Since none of these averages provide a complete picture by itself, a more comprehensive measure of total offensive performance is useful. Such a measure would include the following elements:

The ability to get on base.
The ability to hit with power.
The ability to add value through baserunning.

The first two elements are measured by on-base average and slugging average. A measure of offensive performance, which encompasses both as well as baserunning achievements is Bases per Plate Appearance (BPA). This measure accounts for the net bases accumulated by a player per plate appearance. It is calculated as follows:

BPA = (TB + BB + HB + SB - CS - GIDP) / (AB + BB + HB + SF)

Where:

BPA = Bases per Plate Appearance
TB = Total Bases
BB = Bases on Balls
HB = Hit by Pitch
SB = Stolen Bases
CS = Caught Stealing
GIDP = Grounded into Double Plays
AB = At Bats
SF = Sacrifice Flies

The numerator accounts for all of the bases accumulated by a player, reduced by the number of times he is caught stealing or erases another runner by grounding into a double play. The denominator accounts for the plate appearances when the player is trying to generate bases. Sacrifice hits are not included as plate appearances, since they represent the successful execution of the batter's attempts to advance another runner rather than himself.

Major league BPAs for the past six years are shown below:

Year	1992	1993	1994	1995	1996	1997
BPA	0.423	0.446	0.467	0.463	0.471	0.465
Players over .550	13	29	38	37	41	34
Players over .600	4	8	16	15	21	15

Offensive production peaked in 1996. However, Larry Walker recorded the highest BPA in the past six years in 1997. Of the ten BPAs over .700 in the past six years, Barry Bonds has four and six others have one each.

Player	Team	Year	BPA
Larry Walker	Colorado	1997	0.770
Jeff Bagwell	Houston	1994	0.768
Mark McGwire	Oakland	1996	0.765
Frank Thomas	Chicago (A)	1994	0.747
Albert Belle	Cleveland	1994	0.741
Barry Bonds	San Francisco	1993	0.740
Barry Bonds	San Francisco	1994	0.738
Barry Bonds	Pittsburgh	1992	0.730
Barry Bonds	San Francisco	1996	0.730
Ken Griffey, Jr.	Seattle	1994	0.708

Following is a list of players with enough plate appearances to qualify for the batting title with a BPA of .550 in 1996 or 1997:

Bases per Plate Appearance (BPA) of .550+ in 1996 and 1997

		1996				1997
	1996	BPA	LG		1997	BPA	LG
1	McGwire, M.	0.765	A	1	Walker, L.	0.770	N
2	Bonds, B.	0.730	N	2	Bonds, B.	0.696	N
3	Sheffield, G.	0.690	N	3	McGwire, M.	0.689	A/N
4	Anderson, B.	0.689	A	4	Bagwell, J.	0.682	N
5	Burks, E.	0.683	N	5	Griffey, K. Jr	0.676	A
6	Griffey, K. Jr.	0.683	A	6	Piazza, M.	0.652	N
7	Thome, J.	0.668	A	7	Lankford, R.	0.651	N
8	Belle, A.	0.660	A	8	Thomas, F.	0.649	A
9	Gonzalez, J.	0.655	A	9	Thome, J.	0.640	A
10	Rodriguez, A.	0.653	A	10	Biggio, C.	0.625	N
11	Bagwell, J.	0.651	N	11	Justice, D.	0.620	A
12	Martinez, E.	0.651	A	12	Burnitz, J.	0.613	A
13	Caminiti, K.	0.647	N	13	Galarraga, A.	0.613	N
14	Thomas, F.	0.646	A	14	Vaughn, M.	0.611	A
15	Larkin, B.	0.641	N	15	Martinez, E.	0.600	A
16	Galarraga, A.	0.632	N	16	Hundley, T.	0.598	N
17	Knoblauch, C.	0.625	A	17	Martinez, T.	0.596	A
18	Vaughn, M.	0.618	A	18	Williams, B.	0.589	A
19	Higginson, B.	0.617	A	19	Gonzalez, J.	0.584	A
20	Ramirez, M.	0.607	A	20	Mondesi, R.	0.581	N
21	Palmeiro, R.	0.600	A	21	Greer, R.	0.578	A
22	Vaughn, G.	0.599	A/N	22	Snow, J.	0.570	N
23	Buhner, J.	0.592	A	23	Caminiti, K.	0.569	N
24	Gilkey, B.	0.591	N	24	Sheffield, G.	0.569	N
25	Hundley, T.	0.590	N	25	Delgado, C.	0.566	A
26	Sosa, S.	0.590	N	26	Salmon, T.	0.565	A
27	Williams, B.	0.586	A	27	Ramirez, M.	0.565	A
28	Jaha, J.	0.583	A	28	Higginson, B.	0.565	A
29	Jones, C.	0.582	N	29	Buhner, J.	0.562	A
30	Piazza, M.	0.580	N	30	Gwynn, T.	0.562	N
31	Alomar, R.	0.576	A	31	Garciaparra, N	0.560	A
32	Rodriguez, H.	0.573	N	32	Davis, C.	0.559	A
33	Lankford, R.	0.573	N	33	Anderson, B.	0.555	A
34	Greer, R.	0.571	A	34	DeShields, D.	0.550	N
35	Klesko, R.	0.570	N
36	Nilsson, D.	0.568	A
37	Salmon, T.	0.561	A
38	Bichette, D.	0.559	N
39	Lofton, K.	0.558	A
40	Finley, S.	0.558	N
41	Castilla, V.	0.550	N

The 1997 list includes 22 repeaters from 1996. Walker had a BPA of. 635 in 1996 but didn't have enough plate appearances to qualify. Larkin and Burks were over .550 in both years but didn't have enough plate appearances to qualify in 1997. Four players who were over .600 in 1996 fell below .550 in 1997 (Belle .491, Alex Rodriguez .546, Knoblauch .549 and Palmeiro .520). Three other regulars fell off the 1997 list. Kenny Lofton was on it for four straight years before dropping to .488 in 1997. Dante Bichette and Sammy Sosa were both on it for three years before falling to .509 and .503 respectively.

The biggest surprise on the 1997 list is Jeremy Burnitz who quietly put together an outstanding season for Milwaukee. Others who could be considered surprises are J.T.Snow, Carlos Delgado and Delino DeShields who had a BPA of .394 in 1996. Nomar Garciaparra made the list as a rookie. Two players had BPAs under .350 in 1997 and, as would be expected, both are shortstops. Gary DiSarcina was at .315 and Mike Bordick at .314.

The following players compiled a batting average over .300, an on- base average over .400, a slugging percentage over .500 and bases per plate appearance over .600 in 1996:

	BAVG	OBA	SLG	BPA
Larry Walker	0.366	0.452	0.720	0.770
Mike Piazza	0.362	0.431	0.638	0.652
Frank Thomas	0.347	0.456	0.611	0.649
Craig Biggio	0.309	0.415	0.501	0.625
David Justice	0.329	0.418	0.596	0.620
Mo Vaughn	0.315	0.420	0.560	0.611
Edgar Martinez	0.330	0.456	0.554	0.600

Thomas has made this list for the past five years. Martinez has been on it for three and Vaughn has been on it for two. This list was twice as long in 1996 when fourteen players made it.

Also of interest is a list of players with BPA of over .550 in 1997 who, for one reason or another, did not have enough plate ap- pearances to qualify for the batting title. Following is a list of players with 100 or more plate appearances who fell short of having enough playing time to qualify for the batting title:

Player	BPA	Comments
Turner Ward	0.638	Fringe player had career year for Pirates.
Jon Nunnally	0.636	Made big late-season impact in Cincinnati.
Matt Stairs	0.619	Also on this list in 1996.
Barry Larkin	0.596	Should be back on big list in 1998.
Ellis Burks	0.588	Also on this list in 1994 and 1995.
Todd Greene	0.588	Going strong before injury.
Mike Kelly	0.583	May finally be arriving.
Eric Davis	0.580	A regular on this list.
Bill Spiers	0.573	Career year at age 31.
Juan Samuel	0.570	Also on this list in 1994 and 1995.
Jeff Reed	0.570	Backup for Manwaring (BPA of .299).
Aaron Ledesma	0.563	Limited playing time.
Reggie Sanders	0.563	Another regular on this list.
Mark Smith	0.559	Productive hitter in limited role.
Kevin Young	0.557	Led Pirates in homers.
Javier Lopez	0.555	Hit more homers than McGriff and Jones.

This list may be of particular interest to fantasy league players. It includes players who may be undervalued in 1997 because of injury-plagued seasons in 1996 (Larkin, Burks, Davis, Sanders, Young). It also contains relatively unknown players who may be on the verge of stardom (Nunnaly, Stairs, Kelly, Greene). Some of the names on this list in 1996 who had productive years in 1997 were Walker, Stairs, Reggie Jefferson, Brian Giles and Jim Edmonds. Manny Ramirez was on this list in 1994 before moving to the big list the next three years.

Bill Gilbert 11/3/97 (73623.2146@compuserve.com or billgilbert@postoffice.worldnet.att.net )

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