1. Overcoming the Sub-Optimization Hurdle
To prevent the sub-optimization trap caused by ROI, management accountants use a metric called Residual Income (RI). Instead of measuring efficiency as a percentage, RI measures performance as an absolute cash value. It tracks the net operating profit remaining after deducting the minimum dollar return required to cover the cost of the capital assets used.
2. Mathematical Equation and Blueprint
𝐑𝐞𝐬𝐢𝐝𝐮𝐚𝐥 𝐈𝐧𝐜𝐨𝐦𝐞 (𝐑𝐈)=𝐎𝐩𝐞𝐫𝐚𝐭𝐢𝐧𝐠 𝐏𝐫𝐨𝐟𝐢𝐭 (𝐄𝐁𝐈𝐓)−(𝐀𝐯𝐞𝐫𝐚𝐠𝐞 𝐂𝐚𝐩𝐢𝐭𝐚𝐥 𝐄𝐦𝐩𝐥𝐨𝐲𝐞𝐝×𝐂𝐨𝐫𝐩𝐨𝐫𝐚𝐭𝐞 𝐂𝐨𝐬𝐭 𝐨𝐟 𝐂𝐚𝐩𝐢𝐭𝐚𝐥 (%))
Solving the Sub-Optimization Scenario with RI
Let’s recalculate the previous example using Residual Income:
- Division Capital Employed = $1,000,000 | Current Profit = $240,000 (24% ROI).
- New Project Investment = $200,000 | Expected Project Profit = $36,000 (18% ROI).
- Corporate Cost of Capital = 10%.
Let’s look at how the manager’s total performance updates if they accept the project:
- Combined Capital Employed = $1,200,000
- Combined Operating Profit = $276,000
“𝐂𝐨𝐦𝐛𝐢𝐧𝐞𝐝 𝐑𝐈” = $276,000 −($1,200,000 × 10%)= $276,000 − $120,000 = $156,000 - Contrast: Before the project, the division’s RI was: $240,000 – ($1,000,000 × 10%) = $140,000.
Because accepting the project causes the division’s absolute Residual Income to climb by $16,000, a manager judged on RI will eagerly accept the project, aligning their goals with corporate interests.
3. Strategic Balance Matrix
- Advantages: Eliminates sub-optimization entirely and ensures goal congruence across divisions. It allows companies to apply different cost of capital interest rates to divisions depending on their risk profiles.
- Disadvantages: Because it outputs an absolute dollar figure, it biases comparisons toward larger divisions. A massive, inefficient division can easily report a higher RI cash value than a tiny, highly efficient branch.