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* Add titles * add tidyverse * add more slides * add 1 exercise * mark baseballr code blocks eval false
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‎01_the-baseball-datasets.Rmd‎

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# The Baseball Datasets
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**Learning objectives:**
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- THESE ARE NICE TO HAVE BUT NOT ABSOLUTELY NECESSARY
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- Bookclub overivew
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- Introduction to data sets we will use for the book
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## Overview {-}
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- Book: [Analyzing Baseball Data with R](https://beanumber.github.io/abdwr3e/)
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- Code Repo : [adbwr3edata](https://github.com/beanumber/abdwr3edata)
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- Goal: Learn how to answer baseball questions by learning how to:
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- Access baseball data
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- Manipulate and analyze baseball data with R and tidyverse.
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- Communicate results with quarto and shiny
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## Baseball terms {-}
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Some useful resources for defintions of Baseball terms and statistics:
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[MLB Glossary](https://www.mlb.com/glossary)
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[Baseball reference](https://www.baseball-reference.com/about/)
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[MLB Rules 2025](https://mktg.mlbstatic.com/mlb/official-information/2025-official-baseball-rules.pdf)
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## Lahman Databse {-}
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- Season by Season data from 1871 to current season
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- Consists of multiple tables:
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- People : Player names, DOB, etc
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- Batting : Batting statistics by player / year / 'stint'
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- Pitching : Pitching statistics by player / year / 'stint'
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- Fielding : Fielding statistics by player / year / 'stint'
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- Teams : Team performance by year.
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## Lahman from `R` {-}
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```{r}
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library(Lahman)
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library(tidyverse)
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Teams |>
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slice_tail(n = 3)
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```
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## Example Uses for Lahman {-}
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- Good for answering questions like:
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- What is the average number of home runs per game recorded in each decade? Does the rate of strikeouts show any correlation with the rate of home runs? (*Teams* table)
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- How does the percentage of games completed by the starting pitcher from 2000 to 2010 compare to the percentage of games 100 years before? (*Pitching* table)
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- Which player had the most walks per plate appearance (BB%) in a given year? (*Batting* table)
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## Retrosheet Game-by-Game Data {-}
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- Game logs going back to 1871
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- Teams offensive / defensive stats, starting players, etc
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- All 161 fields documented [here](https://www.retrosheet.org/gamelogs/glfields.txt).
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- [Retrosheet game logs](https://www.retrosheet.org/gamelogs/index.html) are provided for each season as zipped csv files.
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- Some sample data is provided in the books code repo.
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- Example question: In which months are home runs more likely to occur?
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## Retrosheet Play-by-Play Data {-}
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- Event files provided for each game since 1913
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- Data for each play (similar to what you might find on a baseball scoresheet).
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- [Event files](https://www.retrosheet.org/game.htm) are provided as zipped collections by season. One file covers a teams season of games.
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- [Detailed description](https://www.retrosheet.org/eventfile.htm)
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- Example line:
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`play,3,1,bichb001,01,CX,D8/L89XD+.1-3`
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Translation:
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>In the 3rd inning, with the visiting team (Blue Jays) at bat, Bo Bichette hit a double to center field. The ball was lined to center and involved both the center and right fielders. Due to a misplay or error, the batter advanced beyond the expected base. Additionally, a runner who was on first base advanced to third base on the play.
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`
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## Accessing the data {-}
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- Retrosheet provides some (DOS!) tools for parsing the data
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- Instead, book recommends using tools presented in Appendix A
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- Example Question: What is the Major league batting average when the ball/strike count is 0-2? What about on 2-0?
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## Pitch-by-Pitch Data {-}
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![PitchLocation](images/pitchlocation.png)
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- Even more detailed data: Ball release point, trajectory, location at plate, etc.
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- PITCHf/x data from 2008-2017 (?). Replaced by Statcast
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- Example question: What are the chances of a successful steal when the pitcher throws a fastball compared to when a curve is delivered?
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## Statcast {-}
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- Tracks more than PITCHf/x including movement of the individual players
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- Limited data is provided to public by [Baseball Savant](https://baseballsavant.mlb.com)
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- [Baseballr](https://billpetti.github.io/baseballr/) package provides tools to download Baseball Savant data (and more!)
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At the moment, this doesn't seem to be working though with the CRAN version. Need to install the development version:
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```
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# Install the remotes package if you haven't already
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install.packages("remotes")
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remotes::install_github("BillPetti/baseballr")
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```
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```{r, eval = FALSE}
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library(baseballr)
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noah <- statcast_search(start_date = "2016-04-06",
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end_date = "2016-04-15",
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playerid = 592789,
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player_type = 'pitcher')
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```
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- Example Question: How frequently do MLB teams employ infield shifts?
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## Other data on baseballr {-}
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- Scrape extensive data frorm [Baseball Reference](https://www.baseball-reference.com) and [FanGraphs](https://www.fangraphs.com)
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```{r, eval = FALSE}
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library(baseballr)
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bref_standings_on_date("2025-04-12", "NL East", from = FALSE)
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```
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- Retrosheet - but needs a special CLI (See Appendix A)
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## Data used in the book {-}
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- Lahman data from `Lahman` package
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- Small examples for other data are in `abdwr3edata` package
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- Large examples will require downloading data seperately.
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## Exercises {-}
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### Exercise 1: {-}
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This chapter has given an overview of the Lahman database, the Retrosheet game logs, the Retrosheet play-by-play files, the PITCHf/x database, and the Statcast database. Describe the relevant data among these four databases that can be used to answer the following baseball questions.
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How has the rate of walks (per team for nine innings) changed over the history of baseball?
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What fraction of baseball games in 1968 were shutouts? Compare this fraction with the fraction of shutouts in the 2012 baseball season.
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What percentage of first pitches are strikes? If the count is 2-0, what fraction of the pitches are strikes?
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Which players are most likely to hit groundballs? Of these players, compare the speeds at which these groundballs are hit.
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## SLIDE 1 {-}
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Is it easier to steal second base or third base? (Compare the fraction of successful steals of second base with the fraction of successful steals of third base.)
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- ADD SLIDES AS SECTIONS (`##`).
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- TRY TO KEEP THEM RELATIVELY SLIDE-LIKE; THESE ARE NOTES, NOT THE BOOK ITSELF.

‎DESCRIPTION‎

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R (>= 3.1.0)
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Imports:
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bookdown,
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rmarkdown
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rmarkdown,
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tidyverse,
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remotes,
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Lahman,
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baseballr
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Encoding: UTF-8

‎bookclub-r_baseball.Rproj‎

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Version: 1.0
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ProjectId: be451784-a7bb-46ae-b058-c9212b09a2b2
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RestoreWorkspace: Default
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SaveWorkspace: Default

‎images/pitchlocation.png‎

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