Developing the Project Budget: Where the Numbers Become a Commitment
An estimate is a considered view of what work should cost. A budget is something else: an amount of money, allocated by a named body, against a period of time, which somebody will be held to. The transition between the two looks administrative and is not. It is the point at which numbers stop describing the work and start constraining it.
Most of the difficulty sits in a part that sounds procedural. A total can be approved and the project can still be unable to proceed, because the money is not available in the shape the plan needs it. Section 2.4.2 of the PMBOK® Guide Eighth Edition describes budget development as a distinct piece of work for that reason, and it is worth understanding as a sequence.
From estimates to a baseline
Aggregation comes first. Estimates sit against pieces of work, and those roll up into control accounts, which are the levels at which performance will actually be managed and reported. Choosing the control accounts is a real decision. Too few and a cost report tells you the project is overspent without telling you where. Too many and nobody maintains them, and the roll-up quietly stops reflecting anything.
Contingency for identified risk is added next, and it belongs inside the baseline. This is money the project manager expects to use, held against risks that have been analysed, and it is part of what the work is expected to cost. Excluding it produces a baseline that is wrong by design and a project that reports a variance the moment anything anticipated occurs.
Management reserve sits outside the baseline, held by the organisation for what was not foreseen. The project does not draw on it by choice, and using it changes the baseline through a formal decision. Keeping the two apart is what allows a sponsor to distinguish a project that is consuming what it planned to consume from one that has met something nobody predicted.
What emerges is a cost baseline spread across time: how much, in which periods. That spread is the useful artefact, because it is the only version of the budget that can be compared with anything as the project runs.
Time-phasing and the money that is not there yet
Funding arrives on its own schedule. Organisations release money in quarterly tranches, or at gates, or within a financial year that ends whether the project is ready or not. Comparing the spend curve with the funding profile shows where the plan needs money before the organisation intends to provide it, and that comparison is cheap to do at planning and expensive to discover at the time.
Commitments run ahead of spend, and the budget has to account for the gap. A studio booked, a contractor mobilised, a licence ordered, a hire with a notice period: each of these ties up money at the point of order, and each continues to cost whether or not the work around it is ready. A plan that slips by a month while its bookings do not is paying twice for the same period.
Where the two profiles cannot be made to meet, the plan changes or the funding does. Both are real options and both are the sponsor's decision, which is the whole reason for surfacing it before approval instead of after.
Approved in full, available in quarters
A housing association replaced the system its repairs teams worked from. The business case was approved in full, with a total that everyone was content with, and the board recorded the approval at its April meeting.
The money was released quarterly against the association's own cash planning. The plan needed roughly half the total in the first quarter, because the supplier's mobilisation payment, the data migration work and the licence purchase all landed early. No one had laid the spend curve against the release profile, because the total was approved and that felt like the hard part.
The supplier could not be instructed until the second tranche. Mobilisation started seven weeks late, the migration specialists who had been held for the project were reassigned, and the eventual cost of the delay was more than the cost of the finance charge the association had been avoiding. The total never changed. Understanding how a cost baseline is phased, and how to test it against the way an organisation actually releases money, is budgeting ground that Omega's PMP® Exam Preparation goes over carefully.
What approval commits you to
The baseline becomes the thing you report against, and it stops moving. From approval onwards, the comparison that matters is between what has been spent and what the baseline said would have been spent by now, and that comparison is only meaningful if the baseline is left alone. A baseline quietly adjusted each month to match reality is a record of what happened, and it cannot show anyone what went differently from the plan.
Forecasts move, and they are the honest place for new information. The approved figure describes the commitment; the forecast describes what the project now expects. Reporting both, with the difference explained, is what allows a sponsor to act while acting is still useful.
Changes to the baseline go through a decision, not an adjustment. Somebody with authority agrees that the commitment has changed, and the reason is recorded. Where that discipline is missing, the number in the board pack drifts, and the project loses the ability to say whether it is over or not.
For a PMP® candidate, the difference worth holding firmly is between an approved amount and available funding. A scenario in which the budget is agreed, the estimate is sound and work still cannot start is usually describing a funding constraint, and the useful response is a conversation about phasing, not a review of the estimate.
The test takes an afternoon. Put the spend curve and the funding release profile on the same sheet and look for the periods where one sits above the other. Where you find one, you have found either a plan to reshape or a conversation to have with your sponsor while there is still time for it to change something.
Interested in going further?
Building a budget a board can approve, and being able to explain what the approval does and does not make possible, is a defining part of the role. Omega's PMP® Exam Preparation covers estimating, budgeting and cost control as one connected chain of decisions.
The PMBOK® Guide Eighth Edition is the place to see how estimates, the cost baseline and funding requirements fit together.
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References
A123: The PMBOK 8 Finance Performance Domain: What It Really Covers
A124: Cost Is Not the Same as Value
A125: Budget vs Cost Baseline vs Funding
A126: Contingency Reserve vs Management Reserve
A127: CPI and SPI Explained Without Formula Memorisation
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