# Tijuana Bronze Machining: Teaching Commentary

Essay by EMBA2007University, Ph.D. April 2006

OVERVIEW

This is a basic case in Activity-Based Costing (ABC) and Activity-Based Management (ABM). There is enough richness to the fact-situation to create a non-trivial calculational challenge for students without taking the case beyond an "introductory" level. Also, the business context for the calculations is rich enough to support good discussion on the managerial implications.

I use Tijuana Bronze as the introductory case on ABC/ABM in the required managerial accounting course at Tuck and at Babson. The eight assignment questions force students to address the ABC calculations and the ABM managerial implications. Answers to the assigned questions are shown below.

Question 1. Product Costs per Unit - Current System

Valves

Pumps Flow

Controllers

Material \$16.00 \$20.00 \$22.00

Direct Labor 4.00 8.00 6.40

(439% of Direct Labor \$)

Standard unit cost \$37.56 \$63.12 \$56.50

Machine depreciation \$270,000

Set-up labor 2,688

Receiving 20,000

Materials handling 200,000

Engineering 100,000

Packing and shipping 60,000

Maintenance 30,000

Total run labor = 9,725 hours x \$16 = \$155,600

Overhead rate = 682,688 / 155,600 = 439%

Question 2.

Estimated "Contribution Margin" for Products

Valves

Pumps Flow

Controllers

Revenue \$57.78 \$81.26 \$97.07

Variable Costs--Material only 16.00 20.00 22.00

Contribution 41.78 61.26 75.07

or

Assume Labor is Variable (case says only direct material is short-run variable).

Run Labor 4.00 8.00 6.40

Set-up Labor ~.02 ~.05 ~.48

4.02 8.05 6.88

Contribution \$37.76 \$53.21 \$68.19

Question 3. Revised Product Unit costs per "More Modern View"

Valves

Pumps Flow

Controllers

Material \$16.00 \$20.00 \$22.00

(48%)

7.68

9.60

10.56

Set-up Labor .02 .05 .48

Direct Labor 4.00 8.00 6.40

(\$42.59 per machine hr)* 21.30 21.30 8.52

Revised standard cost \$49.00 \$58.95 \$47.96