Pennant ChaseActivity 01BaseballGrades 6–12

The Value Draft

You are about to build a baseball team out of players from a hundred years of history. Before you pick anyone, you need a theory about what makes a player valuable. By the end of the season you'll know whether you were right.

NameTeamLeague

Part One · Before the draft

Commit to a theory

Every general manager has a theory, even the ones who don't know it. Yours goes on paper now, before you see the player pool, so you can't quietly change it later.

In one sentence: what makes a baseball player worth drafting?

Rank the three stats you plan to draft on — 1 is most important
Rank	Statistic	Why this one?
1
2
3

A vocabulary check first

Batting average (AVG) — hits ÷ at-bats. The famous one. Notice what it ignores.
On-base percentage (OBP) — how often a batter reaches base at all, walks included.
Slugging (SLG) — total bases ÷ at-bats. A double counts double, a home run counts quadruple.
OPS — OBP + SLG, jammed together. Crude, but it works surprisingly well.
ERA — earned runs a pitcher allows per nine innings.
WHIP — walks and hits allowed per inning. Roughly, how much traffic a pitcher lets on base.

Counting stats (home runs, RBI, wins, strikeouts) go up the longer you play. Rate stats (AVG, OBP, ERA, WHIP) describe how well you play per opportunity. Keep the difference in mind while you draft — it will matter.

Prediction: where will your team finish, and what will carry it?

Part Two · The draft

Build the roster

Fill this in as you pick. The "Why" column is the important one — a single honest phrase is enough. "Best hitter left" counts. So does "needed a catcher."

Draft log
Pick	Player	Pos	Key stat that sold you	Why you took him here
1
2
3
4
5
6
7
8

Two things to notice while you're picking

Scarcity. There are more good first basemen than good catchers, and you need a catcher. At some point you'll take a worse player because of where he stands on the field. Write down the pick where that first happens.

Opportunity cost. Every pick is also a decision not to take everyone else still on the board. When you make a pick you're unsure about, note the name of the player you passed on. You'll want it later.

Part Three · During the season

Keep the log

Check in on your team on a schedule your teacher sets. This takes about a minute. Do not skip weeks — the gaps are what ruin the analysis at the end.

Team tracking log
Date	W	L	Runs scored	Runs allowed	Team AVG	Team OBP	Team SLG	Team ERA

Player watch

Pick three players you drafted. Record the numbers they put up in real life, then the numbers they're putting up for you. The difference is the most interesting thing on this page.

Real career vs. your league
Player	Real AVG	Your AVG	Real OBP	Your OBP	Real HR rate	Your HR rate

Part Four · After the season

Explain what happened

A. The league table

Working with the class, build one table with a row for every team in the league: wins, runs scored, runs allowed, team AVG, team OBP, team SLG, team ERA.

Now rank the teams three separate times — once by batting average, once by on-base percentage, once by slugging. Compare each ranking to the actual standings.

Which ranking looked most like the real standings? Which looked least like it?

B. Making a picture of it

Plot team OBP on the horizontal axis and runs scored on the vertical axis, one dot per team. Do it again with team AVG. One of those clouds of dots will line up better than the other.

The question underneath: batting average treats a walk as nothing and a home run the same as a single. On-base percentage counts the walk. Slugging counts the extra bases. If your two scatterplots look different, you've just measured how much those things are worth.

C. Grade your own theory

Go back to Part One. Were the three stats you ranked the right ones? Which one would you drop, and what would you replace it with?
Find a player on your roster whose numbers in your league came out noticeably worse than his real career. Give two possible explanations — one about the simulation, one about luck. How would you tell them apart?
Pick the moment in your draft where you took a player because of his position rather than his stats. Estimate what that cost you. Was it worth it?
Find the best hitter in the entire league by OPS. Did his team win? If not, what does that tell you about how much one player can do?
Two of your teammates ran opposite strategies — one drafted hitters early, one drafted pitchers early. How did each finish? Is one season enough evidence to say which strategy is better? Explain what would count as enough.
You get one do-over pick. Which one, and who would you take instead? Use a number to defend it.

Final write-up: your revised theory of what makes a player valuable

Extension

What is the engine doing?

Nobody rolled dice on a field. A program decided every one of those plate appearances. Before your teacher tells you anything, write down your best guess at the steps it must take.

To simulate one plate appearance, the program probably has to…

Three things worth testing

If a hitter reaches base 35% of the time and the pitcher allows it 30% of the time, what happens? Should the answer be closer to the hitter's number, the pitcher's, or the middle? Look at real matchups in your league and see.
Once the engine decides a ball was hit, it still has to decide what kind of hit. What information would it use to choose between a single and a double? Would a fast runner's single ever become a double?
Your .320 hitter batted .270. Run the numbers: over 500 at-bats, how far from .320 could pure chance plausibly land? Is .270 inside that range or outside it?

The sim engine primer gives you the math to answer the first one exactly.

Teacher guide

Running The Value Draft

Timing

One period to launch (theory + draft), 10–15 minutes a week for tracking, and two periods at the end for the league table, the scatterplots, and the write-up. The season length is a league setting, so you can size it to the calendar — ask for a season that finishes with two weeks to spare.

The point of the unit

Students arrive believing batting average is the measure of a hitter. The league data almost always shows on-base percentage and slugging tracking runs scored more closely than average does, and students discover it themselves rather than being told. That reversal is the unit. Everything else is scaffolding.

Grade the Part One prediction and the Part Four revision as a pair. A student whose theory was wrong and who can say precisely how they know it was wrong has done the assignment perfectly.

Where classes get stuck

Missing weeks in the log. The single most common failure. Consider a shared class spreadsheet so a student who misses a check-in can recover the data.
Small samples read as facts. Students will announce that pitching-first beats hitting-first based on one team's finish. Push on it every time: how many seasons would you need? This is the seed of the law-of-large-numbers conversation in the primer.
Counting vs. rate confusion. Someone will argue their player is better because he has more RBI in more games. Worth a whole-class detour when it appears.

Differentiation

Lighter: Have the computer distribute rosters and assign teams. Students still track and analyze, and you skip the draft period entirely. It also means nobody can attribute results to their own drafting skill, which makes the analysis cleaner.
Heavier: Ask for the correlation coefficient rather than an eyeballed scatterplot, and have students compare r for AVG, OBP, SLG, and OPS against runs scored. Add pitching: does team ERA or team WHIP better predict runs allowed?
Cross-curricular: Restrict the player pool to a single decade and pair it with a history unit. A 1920s pool and a 1970s pool produce visibly different baseball, and students will ask why.

Setting up the league

Email guy@pennantchase.com for a free class league. Say your sport, class size, and how many weeks you have.
Send a spreadsheet of logins you'd like created and the accounts get made in bulk. Do this rather than having students sign up — the site blocks repeated sign-ups from one IP address, and a class on a school network trips that.
Some school district mail servers block mail from pennantchase.com. If a reply never arrives, ask IT to allow the domain or write from a personal address.
Pairing students as co-general-managers halves the tracking load and roughly doubles the quality of the arguing.