How to Know When a Project Is No Longer Worth Finishing
Every portfolio contains at least one project where the economics have quietly turned.
The original business case was sound. The work started in good faith. But somewhere along the way - through delay, scope change, market shift, competitor action, or the slow accumulation of small problems - the project crossed a line. The cost remaining to finish it is now higher than the value remaining to be realised. Continuing is no longer a delivery decision. It is an investment decision, and the numbers no longer work.
Most organisations never see that moment coming. They continue investing because cancelling is politically expensive, because nobody is formally asked to test whether the original case still holds, and because the function that should be asking that question is busy reporting on whether the project is hitting its milestones.
This is the difference between project delivery health and project investment health. A traditional PMO reports on the first. A Value Management Office reports on both.
The metric built to identify that moment is DIPP - Devaux’s Index of Project Performance. It is one of the most useful concepts in modern project economics, and it is the one most portfolio leaders have never been introduced to.
Where the concept comes from
DIPP was developed by Stephen Devaux as part of his three-decade body of work on managing projects as investments. The premise is simple: if a project is an investment, then at any point in its life there is a calculable answer to the question "given what we now know, should we still be investing in it?" DIPP gives you that answer as a ratio.
Devaux’s thinking is increasingly aligned with where PMI and the wider profession are moving: away from measuring project completion alone, and toward measuring value delivery. The language of investment, return, and economic impact is entering the mainstream of project management for the first time. DIPP is part of that shift.
It is worth being clear about how DIPP relates to drag cost, the other Devaux concept widely used in Flow Economics work. Drag cost tells you what delay is costing. DIPP tells you whether the project still deserves the next pound of investment. The two metrics answer different questions, and a function using both has a far more complete view of portfolio economics than one using either alone.
What DIPP actually calculates
At its simplest, DIPP compares the value still expected from the project with the cost still required to complete it. In Devaux’s full formulation, the calculation can also adjust for acceleration or delay value, but the operating logic is straightforward:
DIPP = expected value to be realised ÷ cost to complete from this point forward.
The critical word is "from this point forward". Sunk costs - money already spent, time already invested - are not part of the calculation. They are irrelevant to the investment decision being made today. The only question is whether, given everything that is currently true, the remaining value justifies the remaining cost.
A DIPP above one means the project is still worth completing. The value you will receive is greater than what it will cost to get there.
A DIPP below one means the economics have inverted. It will cost more to finish than you will get back. The project may still have strategic reasons to continue - reputational, regulatory, contractual - but those reasons should now be made consciously, with full visibility of the economic consequence.
Why "from this point forward" matters
The hardest part of using DIPP is not the calculation. It is the discipline of ignoring sunk costs.
Most organisations cannot do this. When a project has consumed eighteen months and several million pounds, the conversation about cancelling it gets dominated by what has already been spent. The accurate response is that none of that money is coming back, and continuing or stopping should be decided on the basis of what comes next.
That is not how the discussion actually goes. It goes "we have spent too much to stop now" - a sentence that, in economic terms, is exactly backwards. The more you have already invested, the less it matters to the next decision. What matters is the cost to complete versus the value remaining.
DIPP forces the conversation into the right frame. It strips out the sunk cost and asks the only question that matters today: is the remaining return greater than the remaining investment?
What changes when a portfolio uses DIPP
A function that calculates DIPP across its active projects gets a view of investment health most organisations have never had.
Projects that have quietly drifted into negative economics become visible. Without DIPP, these projects continue because nobody is formally measuring whether they still make sense. With DIPP, the deterioration shows up as a number trending downward, and the conversation about intervention or cancellation happens earlier - when there is still value to protect.
The decision to continue funding becomes defensible. Investment committees stop being asked "do you want to keep going?" - a question that invites political answers - and start being asked "the remaining return is X and the cost to complete is Y, what do you want to do?" That is a different conversation, and it is the conversation a Value Management Office is built to enable.
Portfolio-level health becomes calculable. Aggregating DIPP across every active project gives leadership a single view of whether the portfolio as a whole is still worth completing as planned, or whether interventions are required to protect the overall return.
Why the savings from one DIPP-led decision can pay for the function that found it
The economic argument for using DIPP is rarely subtle. In many portfolios of any size, there is at least one project where the economics have turned and nobody has noticed. The cost of finishing it is significantly higher than the value it will produce. Continuing represents real, ongoing waste.
Identifying that project and making a conscious decision about it - whether to cancel, scope down, or continue for strategic reasons with eyes open - releases real money. Capital that was being consumed for diminishing return becomes available for projects with positive DIPP. Constrained resources tied up on work that no longer makes sense get redirected to work that does.
In many organisations, the financial benefit of one DIPP-led cancellation could exceed the cost of building the function that found it. That is what makes the metric one of the highest-leverage investments a portfolio leader can make.
Why DIPP is not the same as project health reporting
Most organisations already report on project health. RAG ratings, milestone tracking, earned value, risk registers.
None of those tell you what DIPP tells you. RAG ratings measure whether a project is being delivered according to its plan. They do not measure whether the plan is still worth executing. A project can be coded green - on time, on budget, hitting milestones - while its DIPP has dropped below one because the value side of the equation has changed. The project is being delivered well. The project is also no longer worth completing. Both facts are true at the same time.
DIPP is the metric that catches that gap. It is what makes "the project is on track" insufficient as a basis for continued investment - and it is what gives a VMO the language to push back on projects that look fine in delivery terms but no longer make economic sense.
Take the next step
If the investment health of your active projects is currently invisible, the PMO to VMO guide explains how to make it visible. It walks through what to start measuring, what to report on, and how to make the case at executive level for treating projects as live investments rather than committed plans.
