Value Stream Mapping ROI: Building the Business Case

A future state only convinces management once it is clear what it delivers and what it costs. The business case separates three things that often get mixed up: capital released once, recurring savings per year and benefits that cannot be credibly expressed in dollars. All amounts in the example are assumptions and are marked as such; replace them with figures from your finance team.

What belongs in the business case

Value stream mapping supplies the quantities: inventory at each stage, cycle times, uptime, scrap, operator count and production lead time, each for current and future state. The business case puts a value on the difference. Assign every effect to exactly one category, and nothing gets counted twice.

• One-time: cash released by the inventory reduction (affects cash flow, not annual profit).
• Recurring per year: carrying cost on the inventory removed, overtime avoided, less scrap, floor space freed up where applicable.
• Non-monetary: shorter lead time, better on-time delivery, fewer expedited orders. Track these as metrics with a target value, and in dollars only with documented data.
• Costs: investments and internal effort for the actions.

Valuing inventory correctly

Inventory is valued at the manufacturing cost of its stage: material plus the processing cost incurred up to that point. A piece of coil is worth less than an assembled finished part. Multiplying the entire reduction by the finished-goods value inflates the benefit.

Separating one-time cash from recurring savings

The $26,370 comes in exactly once, and only if purchase orders and production orders are actually reduced. Otherwise the inventory just sits there. The reduction takes a few weeks until the old stock is used up.

On a recurring basis, the company saves the carrying cost on the value removed: cost of capital plus space, handling, insurance and obsolescence. Many finance departments have an inventory carrying cost rate for this that already includes the interest. In that case, do not add the interest a second time.

Productivity: overtime first, then headcount

In the steering bracket example, the number of operators does not change: in the current state one operator each works at stamping, welding 1, welding 2, assembly and shipping; in the future state one at stamping, three in the cell and one in shipping, so five each time. The effect lies elsewhere: current-state assembly is slower than takt time.

The effective cycle time of assembly is 62 s ÷ (1 − 2%) = 63.3 s, above the 60 s takt time. For 920 good parts, assembly needs 920 × 63.3 s = about 58,200 s, or about 970 minutes instead of the 920 minutes available. That is about 50 minutes of overtime per day. The future-state cell is below takt time at 56 s ÷ 95% ÷ (1 − 1%) = 59.5 s.

Quality, lead time and floor space

Scrap is easy to value, but only with an action that removes the root cause. The future-state template assumes 1% instead of 2% scrap for the cell. For 920 good parts, 920 ÷ 0.99 = 929.3 parts are then produced instead of 920 ÷ 0.98 = 938.8, about 9.5 fewer parts per day or about 2,090 parts per year. At an assumed $8.00 per part, that is about $16,700 per year. Carry this item as a target scenario until the root cause has been shown to be eliminated.

Production lead time drops from 11.3 to 4.0 days. This improves responsiveness and reduces dependence on forecasts, but it only turns into dollars if you have documented costs such as premium freight, contractual penalties or lost orders. Freed-up floor space only counts if it is used for something else, rent goes away or a planned expansion is avoided.

Cost of the actions and payback

Costs include investments, outside support and the team’s internal effort. The simple payback period divides the costs by the recurring savings; the one-time cash release is shown separately, if at all, or deducted from the costs up front. Show both views openly side by side.

• Assumption SMED at stamping (changeover 60 to 10 min): $8,000.
• Assumption setting up the welding and assembly flow cell (layout, fixtures, relocation): $25,000.
• Assumption TPM for uptime in the cell: $6,000.
• Assumption supermarkets and kanban (racks, containers, cards, training): $4,000.
• Assumption internal project effort: $12,000.
• Total: $55,000.

Common mistakes

• One-time effect counted as annual savings: released capital comes in once; only the carrying cost on it recurs every year.
• Double counting: adding interest on top of a carrying cost rate that already includes it, or counting the same hour as overtime and as a productivity gain.
• Inventory only shifted: if the supplier delivers daily, it may hold the coils itself and add that to the price. Offset price increases and inventory held at the customer or supplier.
• Everything valued at finished-goods value: value raw material and work in process at the manufacturing cost of their stage.
• Lead time converted to dollars without evidence: better to track it as a metric with a target value.
• Forgotten costs: plan for internal effort, start-up losses and training.

In the editor

In Pro mode, the “Costs” tab shows tied-up capital based on the value per piece you enter on each inventory, supermarket and FIFO lane, and the carrying cost per year at an adjustable rate (default 10%). On each kaizen burst you can enter investment and saving per year; from these the editor calculates the simple payback in months, without the cash effect. With the current/future comparison you can set the metrics against a saved state or a JSON file. Leave purchased parts without a value per piece if, as in the example, they are not part of the comparison.

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