The strongest disruption evidence compares an affected period with an unaffected one. On projects that went wrong early there is no unaffected period, which removes the best method and does not remove the loss. Working out what remains is part of loss and expense claim preparation.
The options that remain are weaker and some of them are still worth using. The important thing is to know which, and to be straight about what each proves.
Checking whether a baseline really is absent
Disruption is rarely uniform. One trade, one area, one floor may have run normally while others did not.
A baseline from part of the works, carefully identified, is better than no baseline at all.
This is worth a proper look before the method is abandoned, and it is often skipped.
Comparison with other projects
Where the same contractor carried out comparable work elsewhere, that output can serve as a baseline.
The comparison has to be genuinely comparable in work type, scale and conditions, and differences have to be addressed.
It is weaker than an internal comparison and stronger than a factor table.
Comparison with the tender allowance
The tender build up shows what output the contractor expected to achieve, which is a baseline of a kind.
Its weakness is obvious: the other side will say the tender was optimistic, and sometimes it was.
Where the tender can be shown to have been built up carefully, from established rates, the objection is weaker.
Published output data
Industry output figures for standard operations exist and can serve as a reference.
They describe typical conditions, which the project by definition did not have, so adjustment is needed and contestable.
Used as a cross check rather than as the primary basis, they have some value.
Reframing as prolongation
Where the project also finished late, the prolongation route may capture a large part of the same loss and is proved differently.
Time related cost for the extended period is evidenced from the accounts and the programme rather than from productivity records.
On a badly disrupted project this is frequently where the recoverable money actually is.
Narrowing the claim
One activity, one period, where the records happen to be good, proved properly.
That claim is smaller and it settles, where the whole project claim does not.
It also establishes a principle, which sometimes moves the rest of the negotiation.
What not to do
Present a total cost claim, which compares outturn with tender and asks the assessor to infer the cause.
That approach fails almost everywhere, because it requires the other side to disprove rather than the claimant to prove.
It also makes everything else in the submission look like an afterthought.
Being straight about weakness
A submission that identifies its own evidential limits is treated more seriously than one that does not.
Assessors and tribunals find the weaknesses regardless. Finding them first is worth more than hiding them.
It also makes the strong parts of the claim more credible, which is the practical benefit.
The commercial decision
Where no method works, the question becomes whether to pursue the head at all.
Pursuing an unprovable head costs money and weakens the provable ones beside it.
Dropping it is a decision rather than a defeat, and it is better taken early than after a hearing.
What this says about the next project
Resource allocated to activities, and output by activity, recorded weekly, removes this problem entirely.
That is a small administrative habit with a large effect on recoverability.
On a live project it can start immediately, which protects the period from today onward even if the earlier period is lost.
Apportioning between causes
Where the loss had several causes and only some are the employer’s responsibility, an apportionment is unavoidable. Claiming the whole and leaving the other side to argue for a reduction is a tactic that usually ends with the whole head being refused.
A reasoned apportionment, even a rough one, gives the assessor something to work with and signals that the claim has been prepared rather than assembled. The reasoning matters more than the precision.
Whether apportionment is legally the right approach on particular facts is a question for advice. Commercially, a claim that addresses the problem settles more often than one that pretends it is not there.
What a tribunal does with a weak head
A head that cannot be proved is not simply ignored. It affects how the rest of the claim is read, it adds cost to the proceedings, and in some circumstances it affects the costs of the dispute itself.
That makes carrying an unprovable head into proceedings an active decision with a price, rather than a free option kept open in case it lands.
Which is why the question of what the records support is worth settling before any submission is drafted, and why the answer sometimes is that the disruption head should not be pursued at all.
That conclusion is worth reaching deliberately, with the records in front of you, rather than arriving at it by exhaustion after months of analysis that nobody can use. It is also easier to explain to a client at the start than at the end.
And it leaves the budget available for the heads that will recover, which on a project in this condition is usually where the money actually is.
Where it fits
Establishing which method the records support is the first step and it governs everything after.
Where disruption is not provable, the time position may still be, which is extension of time work.
The habit that prevents the problem belongs with cost control and variations during the works.
Costs incurred that nobody has agreed to pay?
Loss and expense claim preparation sets out the contractual provisions relied on, the costs actually incurred and the link between each matter and each head of cost, in a form that can be tested.