Chapter 15 — Instructor Material

Teaching Notes

What this chapter is really for

Students arrive believing the bar is the fun chapter. It is not; it is the control chapter. The argument to build the session around is the one in §15.1 and §15.7 taken together: the bar is the only reason Bellwether's prime cost lands on its benchmark, and the bar is also capable, by itself, of pushing that prime cost past the benchmark. The same twelve seats do both. If students leave holding that tension, everything else in the chapter is retrievable.

The chapter is also the book's second full costing lab. Chapter 11 costed a plate; this costs a drink. Do not let students treat it as new material — make them notice that the method is identical and that only the omissions differ.

Timing (a 3-hour session, or two 90-minute blocks)

If you only have 90 minutes: §15.1 (15), the costing lab (30), §15.7 (30), §15.8 (15). Assign §15.2, §15.4, and §15.6 as reading with Exercises 15.20 and 15.28 due.

The three hardest points to teach

1. That recording a comp saves you nothing. Students resist this hard. They expect that "tracking" is a cost-reduction activity, and the chapter says flatly that the dollars are identical whether the comp is rung or not. Work it on the board both ways until the net-sales, COGS, and pour-cost lines come out the same. Then ask: so why do it? The answer — that it converts an unexplained variance into a management conversation — is the most transferable idea in the chapter and it generalizes to every control system in Part VII.

2. That a worse percentage can be the better decision. The premium-well table in §15.5 (pour cost 5.8% → 7.6%, contribution \$9.42 → \$10.16) reliably splits a room. Students who have internalized "lower pour cost is better" will argue for the cheap well. Let them argue, then run the annual dollars: \$2,823. This is Chapter 12's argument and students who did not absorb it there get a second chance here.

3. That line cleaning fails its own payback and you do it anyway. §15.4 is deliberately structured to disappoint. Students expect the maintenance-pays-for-itself ending and get \$1,129 of benefit against \$1,560 of cost. The correct lesson — that a control which fails its obvious number may still be the cheapest thing you do, because the largest term is unquantifiable — is genuinely difficult and genuinely important. Do not resolve it too quickly.

Common misconceptions to pre-empt

• "Pour cost is beverage purchases over beverage sales." The single most common error. It is usage, and usage requires an ending count. Kill this in the first ten minutes.
• "Beer is cheap." Students assume draft is the low-cost line. Figure 15.3 puts a craft sixtel at 28.1%. Use the \$2.53-versus-\$1.16 comparison; it lands hard.
• "A pint is sixteen ounces." It is sixteen ounces of glass. Bellwether pours fourteen ounces of beer with an inch of head, and an operator who prices as though it is sixteen has given away two ounces a glass.
• "Over-pour means someone is stealing." It usually means nobody has checked a count in six months. Exercise 15.28 is built specifically to punish students who leap to theft: the variance is far too large to be over-pour and the arithmetic proves it.
• "A discount reduces your price by the discount." It reduces your contribution margin by the discount, which is a much smaller number. This is the single most useful piece of arithmetic in §15.8.
• "Happy hour fills the room, so it works." Only if the guests are incremental. The composite in Case Study 2 is built entirely around students who cannot see the difference.
• "Ice is free." It is four cents. Which is nothing, and \$509 a year, and it is one of four omissions that become three points.

Demonstration ideas

The costing lab (best single activity in the chapter). Bring the physical inputs, or photographs of them: a bottle with a stated case price, a bag of lemons with a price tag, a jar of syrup, a bottle of bitters, a jigger, a shaker tin, and a takeout container. Give teams a drink spec and twenty minutes to build a card, then have each team present its total. The totals will differ, and the differences will be exactly the four lines the chapter says people omit. Nothing else teaches the point as fast.

The pour test. If you have access to a bar or a lab kitchen: a bottle of water with a pour spout, a graduated cylinder, and volunteers asked to free-pour "an ounce and a half." Record every result on the board. The spread — and its direction — will make the §15.7 arithmetic feel earned rather than asserted. Follow it with the same volunteers using a jigger, and time both. Three seconds is the honest figure and students are surprised how small it is.

The tenths drill. Six opaque or dark bottles filled to known levels, students record tenths independently, then reveal the true fills. Compute each student's error and then the class average error. The point is dramatic: individual errors of ±10% collapse to near zero in aggregate, which is exactly why the method works and exactly why chasing a single bottle's disagreement is a waste of a Monday.

Reading Figure 15.5 cold. Project the week-19 count with the ideal and variance columns covered. Ask the room what they would do. Most will say "the pour cost is 23.2%, that's bad." Then uncover the category split and watch the diagnosis change from the bar to the spirits line and possibly one untrained part-timer.

Assessment suggestions

• Best single graded problem: Exercise 15.28. It rewards process over instinct, and the students who "find the thief" fail it.
• Best costing problem: Exercise 15.17, with Exercise 15.18 as a follow-on so students have to re-cost under price movement rather than just cost once.
• Best judgment problem: Exercise 15.37. There is no arithmetic answer; grade the sequence — mix, station, training — and whether the student says anything to anyone before checking those three.
• Best writing problem: Exercise 15.33. Grade on three things: whether the policy attaches a number to generosity rather than withdrawing it, whether the stated purpose is visibility rather than suspicion, and whether the pre-shift language puts the manager's problem at the center instead of the staff's honesty.
• For a longer assignment, Exercise 15.41 (the sensitivity table) plus a one-page memo defending the 28% assumption is the closest thing in the chapter to real plan work.

A note on tone

Two topics in this chapter require care in a classroom.

Responsible service. The ⚖️ callout in §15.7 and the second half of Case Study 2 are not optional and should not be taught as compliance box-ticking. The specific idea worth landing is the one about incentives: if a program rewards volume and a policy limits it, the incentives win. Ask students to name a promotion structure that makes the two point the same way. Most will get there.

Staff and theft. The chapter is deliberate about not writing bartenders as suspects — over-pour is framed as generosity and station design, sweethearting as hospitality with no budget attached. Hold that register. A class that leaves this chapter thinking bar staff are the enemy has learned the wrong thing and will manage badly.