Executive summaries in a viability assessment
The executive summary is the part of a viability assessment that gets published and read. Six figures it has to state, the fields reviewers look for, and how to handle redaction.
An executive summary in a viability assessment has one job: to let a planning officer, a committee member or an objector read two pages and understand what the scheme can afford, what policy asks for, and the size of the gap between them. National viability guidance expects assessments to be prepared on the basis that they will be published, and where exceptional circumstances justify withholding the full appraisal, the summary is the part that still goes into the public domain. Write it last, write it for a reader who will not open the spreadsheet, and state the shortfall in the first paragraph.
Most summaries fail on that last point. They describe the methodology at length and leave the conclusion to be inferred from a table on page 40.
What the summary has to state plainly
Six things, in this order, and each of them in a sentence rather than a cross-reference.
The scheme as applied for, with unit numbers, mix and floorspace. The policy requirement being tested, quoted from the adopted plan with the policy number. The affordable housing and other contributions the appraisal shows as deliverable. The residual land value the appraisal produces. The benchmark land value and how it was derived. And the surplus or deficit, in pounds and as a proportion of gross development value.
A reader who has those six figures can form a view. A reader given a narrative about market conditions cannot, and will ask the council to commission a review, which adds weeks and a fee.
Objectivity matters as much as content. The RICS professional statement on financial viability in planning sets reporting and conduct standards for this work, including the duty to report to the same standard whoever pays the fee. A Viability Assessment is strongly expected to be authored by a suitably qualified valuer, and the council will normally have its own consultant review it line by line.
The appraisal summary table and its fields
One table, on one page, with no abbreviations the reader has to decode. The fields that a reviewing surveyor will look for are the gross development value split between private and affordable, the build cost with its source stated, abnormal costs itemised separately from base build, professional fees as a percentage, finance rate and period, contingency, developer return expressed against gross development value, total development cost, residual land value, benchmark land value, and the resulting surplus or deficit.
Two of those fields carry most of the argument.
Build cost needs its source and its date. Where it comes from a published cost index, say which index and which quarter, and state whether the figure includes external works and preliminaries. Where it comes from a contractor's estimate, say so, because a tender price for a specific scheme and an index median are not the same evidence and reviewers treat them differently.
Developer return is the other. National guidance points to a return in the range of 15 to 20 per cent of gross development value as potentially suitable for market housing, with a lower figure appropriate for affordable housing delivered to a registered provider. If your appraisal sits outside that range, the summary is where you justify it, not a footnote in an appendix.
Abnormal costs attract the most scrutiny of any line. Contamination remediation, piling, demolition, flood mitigation and utility reinforcement all belong here with evidence attached, and a utilities capacity assessment is often what substantiates the reinforcement figure.
Stating the policy shortfall rather than burying it
The council is not assessing whether your scheme is profitable. It is assessing whether the policy requirement can be met, and if not, by how much it must be reduced.
So the summary needs a direct comparison: the policy-compliant scheme and the scheme as proposed, appraised on the same inputs, with the difference shown. Where the proposal offers 20 per cent affordable housing against a policy requirement of 35 per cent, say that in those terms and give the cost of closing the gap.
Avoid the construction where the summary says the scheme "cannot viably support" the policy level without saying what it can support. Officers read that as an opening position rather than a conclusion, and it invites the review consultant to test every input rather than the two or three that are actually in dispute.
An Affordable Housing Statement sets out the tenure split and delivery mechanism, and the two documents have to agree. Where they do not, the viability summary is the one that gets quoted back at committee.
Assumptions that belong in the summary
Not all of them. The ones a different valuer could reasonably disagree with.
Benchmark land value method and figure, with the existing use value and the premium shown separately. Sales values per square metre with the comparable evidence date. Build cost base date and the allowance for inflation. Finance rate and the assumed drawdown period. Affordable housing transfer values as a percentage of open market value. Any site-specific abnormal above a stated threshold. The treatment of the Community Infrastructure Levy, which is a fixed charge rather than a negotiable one and should appear as a cost rather than as a contribution.
State the date of the appraisal. Viability evidence has a short shelf life and a summary without a valuation date is worth very little six months later.
Public availability and redaction
National guidance is clear that viability assessments should be publicly available, and that where redaction is justified on narrow grounds, an executive summary should still be published. In practice that means writing the summary as a public document from the start.
Redaction has to be specific and justified, not wholesale. Commercially sensitive material is usually narrow: an unexchanged purchase price, a named registered provider's offer, a contractor's tender build-up. Policy requirements, sales value assumptions, benchmark land value and the affordable housing conclusion are not commercially sensitive, and redacting them tends to produce a committee report that recommends refusal for lack of evidence.
If you redact, mark what has been removed and why, rather than returning a document with blank pages.
Keeping the summary consistent with the appraisal
The commonest technical criticism of a viability assessment is internal inconsistency, and it almost always lands on the summary because that is the part people read.
Check that the unit numbers in the summary match the application drawings and the planning statement. Check that the gross development value in the summary matches the appraisal output rather than an earlier run. Check that any sensitivity analysis quoted in the summary uses the same base case. Check that the contribution figures match the draft heads of terms.
Where the appraisal has been updated after a design change, reissue the summary with a version number and a date. Reviewers who find two summaries with different conclusions in the same file will discount both.
Length and tone for a committee reader
Two pages. Three if the scheme is phased. No methodology section longer than a paragraph, because the method belongs in the body and the committee has read a dozen of these.
Write in plain sentences with the numbers in them. A committee member needs to be able to say what the scheme offers, what policy asks for, what the gap is, and what mechanism will capture any improvement in values before completion. That last point, the review mechanism, deserves its own short paragraph: early or late stage, the trigger, the formula and who holds the money.
One honest uncertainty. The weight a council gives a viability case varies with how recently its plan-making viability evidence was prepared, and a scheme that succeeded on viability grounds in one district will not automatically succeed in the next even on identical inputs.
Where a draft is prepared with AI assistance, the appraisal inputs and the valuation judgement still need a qualified valuer, and the professional directory on PlanScope is the route to sign-off. For specialist technical reports, qualified professional input may be required.
Browse the report types on PlanScope to see what a viability submission sits alongside.
This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
Does a viability assessment have to be published?
National viability guidance expects assessments to be prepared on the basis that they will be made publicly available, other than in exceptional circumstances. Even where that exception applies, an executive summary should still be published. Write the summary as a public document and keep redaction to genuinely commercially sensitive items such as an unexchanged purchase price.
What developer return is accepted in a viability appraisal?
National guidance points to a return in the range of 15 to 20 per cent of gross development value as potentially suitable for market housing, with a lower figure appropriate for affordable housing sold to a registered provider. A return outside that range needs justifying in the summary itself, with scheme-specific reasons rather than a general statement about risk.
How should benchmark land value appear in the summary?
Show the method, the existing use value and the premium as separate figures, then the benchmark total. A single unexplained number is the input most often rejected by a council's review consultant. Where the land was bought recently, state the price and explain how it was treated, because a purchase price is not itself a benchmark land value.
Who should write a viability assessment?
Councils usually expect a suitably qualified valuer, and the RICS professional statement on financial viability in planning sets the reporting and conduct standards for the work. Professional review is strongly advised before submission, because the council will normally commission its own consultant to test every input line by line.
Should the Community Infrastructure Levy appear as a cost?
Yes. The levy is a fixed charge set by the adopted charging schedule rather than something negotiated through the appraisal, so it belongs on the cost side of the summary table. Treating it as a planning contribution, or netting it against section 106 obligations, is a common error that a review consultant will correct.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.