Chapter 03
Replacement versus supporting models
Why the two main shapes of RDI value model differently, and why naming each one separately tends to strengthen the case rather than weaken it.
01
The clean cut between the two shapes
A replacement workflow substitutes for a line that already sits in the project budget. A supporting workflow improves a process the project already runs. The cut is sharper than it sounds, and finance partners feel the difference within a paragraph. Replacement value points at a budget owner; the budget owner can be asked to confirm the line. Supporting value points at a process; the process owner can describe the saving but cannot remove a budget line for it. Both are real. They model differently and they read differently. The case that names each one separately gets read on its merits. The case that blends them gets read with the suspicion the weaker shape attracts. The discipline of separation is the easiest credibility win available to the analyst. A simple test sorts most lines correctly. Ask: if the workflow is removed tomorrow, does a budget line reappear, or does a process degrade? If a line reappears — the photo service is recommissioned, the gate marshal is rehired — the saving is replacement. If a process degrades — meetings run longer, claims files take longer to assemble — the saving is supporting. The test is binary by design. Lines that resist the test usually resist because they are misclassified. Run the test on every benefit claim before assigning it to a section. The minute spent applying it saves an hour later when a reviewer applies it instead.
02
Replacement workflows and how to model them
A replacement workflow takes a cost out of the project. Outsourced progress photo services. Third-party gate marshals. Externally produced monthly reports. Each line has a budget owner, a contracted rate, and a renewal date. The model is direct: identify the line, confirm the rate with the budget owner in writing, estimate the proportion replaced, apply over the contract life, subtract the workflow cost. A worked illustration. A monthly third-party progress photo service at 1,800 euro per month for 24 months is 43,200 euro. A 70 to 90 per cent replacement gives 30,240 to 38,880 euro of avoided cost, less the workflow run-rate. The output is narrow because the inputs are concrete. Replacement workflows are the easiest line to defend, and they should usually open the case. They make the rest of the document credible by association. The largest replacement opportunities tend to live in three places. First, third-party site capture services where the contract has a fixed monthly rate. Second, in-house manual reporting where a named role spends a measurable share of the working week on it. Third, evidence retrieval performed by a project manager who otherwise would not touch a drive. Confirm each line with the budget partner before publishing. The confirmation is not a formality; it is the source. A replacement claim without a confirmation reads as an estimate of someone else´s budget, which is the weakest position a case can take. With the confirmation, the line becomes a fact the reviewer cannot challenge without challenging the budget partner directly.
03
Supporting workflows and how to model them
A supporting workflow improves a process the project already runs. The OAC meeting still happens; it just runs better. The claims process exists; it just produces stronger files faster. The morning routine of the project director still exists; it just routes attention more accurately. The value is real but harder to attribute to a budget line because no budget line disappears. Time-saving is the right model, applied with care. Estimate the hours per occurrence saved. Multiply by frequency. Multiply by loaded cost. Where the saving is shared across many people in small slices — half an hour each across eight people in a weekly meeting — the model should be conservative because each individual saving is hard to verify. A worked feel. A weekly OAC meeting with eight participants saving roughly 25 to 40 minutes each, at a blended loaded rate of 80 to 120 euro per hour, runs at roughly 270 to 640 euro per meeting, or 14,000 to 33,000 euro per year. Publish the band. Acknowledge that the people did not get the time back as a billable hour; instead, the meeting ran on time and decisions arrived faster. A useful convention for supporting workflows is the attribution discount. The raw time-saving is the first number. Apply a discount — typically 30 to 60 per cent — to reflect the fact that not all saved minutes are productively reabsorbed. The discounted figure is the one the case publishes. Reviewers respond well to the discount because it acknowledges what they would otherwise raise themselves. Authors who apply it once tend to apply it permanently because it survives scrutiny better than the gross figure ever does.
04
Blending the two shapes in one case
Most projects carry both shapes. The case benefits from naming each. Open with the replacement value because it is the easiest to defend. Then add the supporting value with its own ranges and assumptions and a clear note on attribution. Finance partners who would have rejected an inflated single number tend to accept the same total when it is presented in its two natural shapes. The discipline is the separation, not the sum. A worked outline: section A is replacement, with each line citing the budget owner and rate. Section B is supporting, with each line giving frequency, hours per occurrence, and the population affected. The executive summary shows the two subtotals and the combined total. The reader who disagrees with the supporting line can still approve on the replacement subtotal alone. That option is itself a kind of credibility. A typical balanced case lands with replacement value somewhere between 40 and 70 per cent of the total operational saving, with supporting value making up the rest. If replacement is below 30 per cent, the case is leaning on time savings the reviewer cannot verify; either narrow the supporting band by tightening the attribution discount, or look harder for replacement opportunities. If replacement is above 80 per cent, the case is probably solid but small; that is also acceptable, and it is more credible than a blended total of similar size that obscures its composition. Show the proportion explicitly.
05
Failure modes around the boundary
Two failure modes recur at the boundary. First, double counting: claiming the avoided cost of an outsourced service and the time saving of the internal owner of that service. The cost line replaces the service; the internal time was already used to manage it. Pick one. Second, attribution drift: claiming a supporting saving that depends on a behaviour change the project has not yet committed to. If the OAC meeting is going to keep its existing length regardless, the supporting saving on that meeting is zero. Both errors are honest. Both look dishonest to a reviewer. The fix is procedural. Walk each line past its owner. Ask whether the saving they are agreeing to is reflected in their plan for next year. If not, do not claim it. The case loses a small number on paper and gains a large amount of trust in the room. A third failure mode worth flagging: the legacy line that survives the change. The team adopts the workflow but keeps producing the old report alongside it for six months because someone senior asked for both. The replacement saving on that line is zero for the duration of the parallel running. An honest case names the parallel-running period explicitly and starts the saving clock at the agreed sunset date. Reviewers value this kind of detail because it shows the analyst has thought about the operational reality rather than the paper plan.
Practice
01. Pick three benefits you would model on your current project. For each, decide whether it is replacement or supporting, name the budget or process owner, and write the source line you would use to confirm the input.
Look for: Three lines, each tagged R or S, each with a named owner and a source. Replacement lines reference a budget rate or contract; supporting lines reference a frequency and a population.
02. Find one line in a draft case that risks double counting at the replacement-supporting boundary. Rewrite it so the same value is claimed only once, and explain in one sentence which shape it belongs to.
Look for: A revised line that picks one shape, drops the duplicate, and gives a one-sentence rationale. The rewrite usually loses a small amount of headline value and earns a noticeable amount of credibility.
Checkpoint
For a current case, can you sort each line into replacement or supporting, name the budget owner or process owner, and confirm there is no double counting at the boundary?
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