Chapter 12 Further Reading: Box Plus-Minus (BPM) and VORP

Annotated Bibliography

This annotated bibliography provides resources for deeper exploration of BPM, VORP, and related box score-based player evaluation metrics.

Foundational Documentation

Myers, D. (2011, updated regularly). "About Box Plus/Minus (BPM)." Basketball-Reference.com.

Summary: The official documentation for BPM from Basketball Reference, explaining the methodology, coefficients, and interpretation guidelines.

Key Contents: - Complete BPM formula and coefficients - Position estimation methodology - Team adjustment details - Historical context and updates

Recommended For: Essential reading for anyone implementing or interpreting BPM.

Link: https://www.basketball-reference.com/about/bpm2.html

Hollinger, J. (2005). Pro Basketball Forecast. Potomac Books.

Summary: John Hollinger's book introducing PER and laying groundwork for box score-based player evaluation. While PER differs from BPM, the conceptual foundation is related.

Key Contributions: - Framework for combining box score statistics - Discussion of rate vs. volume measures - Historical player comparisons

Recommended For: Understanding the evolution of box score metrics before BPM.

Statistical Methodology

Oliver, D. (2004). Basketball on Paper: Rules and Tools for Performance Analysis. Potomac Books.

Summary: The foundational text on basketball analytics, introducing concepts like offensive/defensive rating, four factors, and individual statistical analysis that inform BPM construction.

Key Chapters: - Chapter 3: Evaluating Offense - Chapter 4: Evaluating Defense - Chapter 7: Evaluating Players

Recommended For: Building foundational understanding of basketball statistics.

Kubatko, J., Oliver, D., Pelton, K., & Rosenbaum, D. T. (2007). "A Starting Point for Analyzing Basketball Statistics." Journal of Quantitative Analysis in Sports, 3(3).

Summary: Collaborative paper establishing consensus definitions for basketball analytics concepts including possessions, ratings, and efficiency metrics.

Key Contributions: - Standardized possession estimation - Offensive and defensive rating formulas - Framework for individual vs. team statistics

Recommended For: Understanding the statistical foundations underlying BPM.

RAPM Connection

Sill, J. (2010). "Improved NBA Adjusted +/- Using Regularization and Out-of-Sample Testing." MIT Sloan Sports Analytics Conference.

Summary: The RAPM paper that established the target metric BPM attempts to approximate. Understanding RAPM is essential for understanding BPM's goals and limitations.

Key Insight: BPM coefficients are calibrated to predict RAPM, making RAPM the implicit gold standard for BPM validation.

Recommended For: Understanding what BPM is trying to estimate.

Engelmann, J. (2011). "A New Way to Think About Player Efficiency Rating." ESPN Insider.

Summary: Early work on connecting box scores to plus-minus data, demonstrating that box scores contain significant information about player impact.

Recommended For: Historical perspective on BPM development.

Alternative Metrics

Basketball-Reference. "Win Shares." Basketball-Reference.com.

Summary: Documentation of Win Shares, an alternative cumulative metric that allocates team wins to individual players based on offensive and defensive contributions.

Comparison to VORP: - Both measure cumulative value - Win Shares uses different methodology (marginal offense/defense) - VORP tied to point differential; Win Shares tied to wins

Link: https://www.basketball-reference.com/about/ws.html

Pelton, K. (2012). "ESPN's New NBA Statistics." ESPN Insider.

Summary: Introduction of ESPN's RPM (Real Plus-Minus), which uses BPM as a prior combined with RAPM from lineup data.

Key Contributions: - Hybrid approach combining box scores and lineup data - Discussion of prior weighting by sample size - Comparison of different methodologies

Recommended For: Understanding how BPM fits into modern metric ecosystems.

Defensive Evaluation

Goldsberry, K. (2013). "How Mapping Shot Data Is Changing Basketball Analytics." Grantland.

Summary: Introduction of shot charts and spatial analysis, which reveals what box score metrics like DBPM cannot capture about defense.

Key Insight: Defensive value often invisible in box scores (positioning, contest quality, help defense) may be captured through tracking data.

Recommended For: Understanding DBPM limitations.

Franks, A., Miller, A., Bornn, L., & Goldsberry, K. (2015). "Characterizing the Spatial Structure of Defensive Skill in Professional Basketball." Annals of Applied Statistics.

Summary: Academic treatment of defensive skill measurement using tracking data, demonstrating what defense metrics aspire to capture.

Recommended For: Advanced understanding of defensive evaluation beyond box scores.

Player Valuation

Berri, D. J., Schmidt, M. B., & Brook, S. L. (2006). The Wages of Wins. Stanford University Press.

Summary: Economic analysis of player value in basketball, introducing Wins Produced metric and discussing market inefficiencies.

Key Contributions: - Framework for converting performance to wins - Analysis of salary vs. production relationships - Discussion of market inefficiencies

Recommended For: Understanding economic applications of metrics like VORP.

Lewis, M. (2016). The Undoing Project. W. W. Norton.

Summary: While primarily about Kahneman and Tversky, includes discussion of NBA draft evaluation and how cognitive biases affect player assessment.

Relevance: Metrics like BPM can counter cognitive biases in player evaluation.

Recommended For: Understanding psychological context of quantitative evaluation.

Implementation Resources

nba_api Python Library

Summary: Unofficial Python wrapper for NBA.com statistics API, useful for gathering data needed to calculate BPM and VORP.

Key Features: - Access to box score data - Play-by-play information - Historical statistics

Link: https://github.com/swar/nba_api

Basketball-Reference Data

Summary: Comprehensive historical basketball statistics database with pre-computed BPM and VORP for all players since 1973-74.

Key Features: - Historical BPM/VORP data - Season-by-season statistics - Searchable player databases

Link: https://www.basketball-reference.com

Academic Papers

Fearnhead, P., & Taylor, B. M. (2011). "On Estimating the Ability of NBA Players." Journal of Quantitative Analysis in Sports, 7(3).

Summary: Statistical treatment of player ability estimation, including discussion of shrinkage estimators and uncertainty quantification.

Relevance: Provides theoretical foundation for understanding BPM reliability.

Page, G. L., Barney, B. J., & McGuire, A. T. (2013). "Effect of Position, Usage Rate, and Per Game Minutes Played on NBA Player Production Curves." Journal of Quantitative Analysis in Sports, 9(4).

Summary: Analysis of how player production varies by position and usage, relevant to understanding BPM position adjustments.

Recommended For: Understanding position-based differences in production curves.

Online Resources

Cleaning the Glass

Summary: Subscription basketball analytics site with advanced statistics and analysis, including detailed on/off data that can validate BPM estimates.

Link: https://cleaningtheglass.com

Thinking Basketball (Ben Taylor)

Summary: YouTube channel and website providing detailed player analysis using advanced metrics including BPM, with emphasis on understanding what metrics capture and miss.

Link: https://www.youtube.com/c/ThinkingBasketball

The Ringer NBA Coverage

Summary: Sports media site with regular analytics-informed basketball coverage, demonstrating practical application of metrics like BPM.

Link: https://www.theringer.com/nba

For Beginners

  1. Basketball-Reference BPM documentation
  2. Oliver (2004) - Basketball on Paper (selected chapters)
  3. Myers - BPM methodology explanation
  4. Basketball-Reference Win Shares documentation (for comparison)

For Intermediate Readers

  1. Kubatko et al. (2007) - Statistical foundations
  2. Sill (2010) - RAPM methodology
  3. Pelton (2012) - RPM hybrid approach
  4. Berri et al. (2006) - Economic applications

For Advanced Readers

  1. Fearnhead & Taylor (2011) - Statistical estimation
  2. Page et al. (2013) - Production curves
  3. Franks et al. (2015) - Defensive skill measurement
  4. Original BPM coefficient derivation (if available)

Citation Format

When citing BPM methodology:

Myers, D. (2011). About Box Plus/Minus (BPM). Basketball-Reference.com.
Retrieved from https://www.basketball-reference.com/about/bpm2.html

When citing VORP:

VORP is calculated from BPM using the formula:
VORP = (BPM - (-2.0)) × (% of possessions played)
where -2.0 represents replacement level.
See Basketball-Reference methodology documentation.

For academic citations of the underlying concepts:

Oliver, D. (2004). Basketball on Paper: Rules and Tools for Performance
Analysis. Potomac Books.

Kubatko, J., Oliver, D., Pelton, K., & Rosenbaum, D. T. (2007). A Starting
Point for Analyzing Basketball Statistics. Journal of Quantitative Analysis
in Sports, 3(3).