Run Expectancy and Value Calculation

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Questions and Answers

What is the first step in calculating run expectancy based on the data frame from 2018?

Group by the number of outs

Calculate the mean number of runs scored from any given event (correct)

Create a list of all possible starting states

Calculate the total number of runs scored

What does the variable 'runs future' represent in the data set?

Runs expected from the next game

Total runs scored in a season

Runs scored from the beginning of the event to the end of the inning (correct)

Projected runs for the next inning

In the state with no runners on base and one out, what is the run expectancy?

1.00

0.10

0.49

0.26 (correct)

What is the run expectancy when there are two outs and no runners on base?

0.10 Signup and view all the answers

What state has a run expectancy of just over one run?

Runner on third and one out Signup and view all the answers

What does the run expectancy matrix provide?

Expected number of runs for various game states Signup and view all the answers

How does run expectancy change with increasing outs?

It generally decreases Signup and view all the answers

What is done after calculating the list of run expectancies for each possible starting state?

It is merged into the original data set Signup and view all the answers

What is a run value defined as in this context?

Runs scored plus the run expectancy at the end minus the run expectancy at the start Signup and view all the answers

In the first example provided, what event is suggested to have occurred?

A home run Signup and view all the answers

What was the increase in run expectancy when the batter reached first base with no outs?

0.38 Signup and view all the answers

What role does run expectancy play in measuring batting events?

It provides a context to assess the impact of different events based on outs and base state. Signup and view all the answers

What conclusion can be drawn from the example where the batter got a hit to first base?

The increase in run expectancy is a measurable contribution to the game's outcome. Signup and view all the answers

What does runs value represent?

The sum of runs scored on an event and the difference in run expectancy. Signup and view all the answers

What happens when there are three outs in an inning?

The inning finishes and the run expectancy becomes zero. Signup and view all the answers

Why is it necessary to create a state for three outs?

To represent an ending state that doesn't exist at the start of an event. Signup and view all the answers

How do start and end run expectancy matrices compare?

They are the same except for the addition of three out states at the end. Signup and view all the answers

What is run expectancy at the beginning of an event based on?

Specific game conditions and states. Signup and view all the answers

What must be added to calculate the end run expectancy?

An additional state for three outs. Signup and view all the answers

What does adding an extra state for three outs enable?

It allows the inclusion of a scenario that can only occur after an event. Signup and view all the answers

What is the run expectancy when there are three outs?

It is zero because the inning has ended. Signup and view all the answers

What happens to run expectancy when a runner on third base scores?

Run expectancy decreases due to the runner being gone. Signup and view all the answers

What does the end run expectancy matrix include that the start run expectancy does not?

Extra states where there are three outs. Signup and view all the answers

Why does run expectancy change based on the events occurring in a game?

Because it depends on how many outs and runners are on base. Signup and view all the answers

What is the run expectancy at the start and end of the first event if there are no outs and no one on base?

0 at both the start and end. Signup and view all the answers

In merging the end run expectancy with the main data set, which state is used for the merge?

End state. Signup and view all the answers

How does run expectancy change if a player is put out?

Run expectancy decreases. Signup and view all the answers

What is the likely run expectancy when there are no outs and a runner is on first base?

0.887. Signup and view all the answers

What value does the end run expectancy matrix retain from the start run expectancy?

The first 24 rows. Signup and view all the answers

Study Notes

Run Expectancy Calculation

Run expectancy (RE) is calculated based on data from 2018.
Mean number of runs scored in an inning is calculated for each event.
Code groups events by starting state (runners on base, outs).
Run expectancy is calculated for each possible starting state.
Example: 0 runners on base, no outs: RE = 0.49 (average of runs scored in that state).
Example: 1 out, no runners: RE = 0.26.
RE decreases as the number of outs increases.
Starting state with runner on 3rd, 1 out: RE ≈ 1.0.
RE values are calculated for each starting state.

Run Expectancy Matrix

The run expectancy matrix is a table of RE values for various base states.
Each row represents a specific configuration of runners and outs (starting state).
Values represent average runs expected for each starting state.
Values change depending on the number of outs and the number of runners on base.

Run Value Calculation

Run value (RV) measures the contribution of an event.
RV = Runs scored + (End RE - Start RE)
Start RE is the RE at the event start.
End RE is the RE at the event end.
An event ending with 3 outs and no runs scored, has a RV of zero.
The run value calculation considers the change in RE during an event.

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Description

This quiz explores the concepts of run expectancy (RE) and run value (RV) calculations in baseball using 2018 data. You will learn how average runs are scored based on different starting states, as well as how to interpret the run expectancy matrix. Test your understanding of these key metrics that impact game strategy.