The cost of unproven work: when the job is done but not proven

Where the term comes from

FortyFive uses the phrase to describe a gap that most field-services businesses recognise but rarely name. A job can be marked complete without leaving a record that the business accountable to the customer can approve and pay against. The evidence sits in one place, the approved changes in another and the agreed rates in a third. Someone has to bring them back together later, and that effort, delay and risk is the cost of unproven work.

We set out the idea in detail in our white paper, The cost of unproven work.

Why field services is where it hides

Field work in connectivity and telecoms usually passes through a chain: the end customer, an operator or integrator, a specialist provider, regional subcontractors and finally the engineer on site. Each handover is a chance for the record to fragment. The people who approve the work are rarely on site, and the people on site are rarely the ones who issue the invoice. The further the work travels from the accountable business, the more the proof depends on messages, photos in personal phones and recollection.

The five costs

The gap shows up as five recurring costs, four operational and one financial:

1. The revisit that could have been avoided: a return trip because an acceptance check was missed or the record was incomplete.
2. The rework nobody can attribute: a later fault that cannot be traced because nobody recorded what was tested.
3. The invoice that has to be reconstructed: billing becomes a negotiation because the approval for extra work is hard to find.
4. The payment waiting for a decision: a valid invoice waits because acceptance is incomplete.
5. The cost of carrying the gap: the working capital tied up between work done and payment received. Each of the other four makes this done-to-paid gap longer.

See them explained on our About page.

How to tell if you have it

• Invoices are regularly queried for missing photos, sign-off or approval of extra time.
• Delivery managers spend hours each week chasing evidence after jobs have closed.
• Engineers return to sites to complete checks they could have done on the first visit.
• Disputes about faults end in a credit note because nobody can show what was tested.
• Partners complain that they are paid weeks after the work, and you are not sure why.

How to measure it

Start with four measures, using consistent definitions across teams and suppliers:

• Evidence-related queries: jobs queried because required records are missing or unclear, as a share of completed jobs.
• Review effort: staff time spent obtaining records and resolving those queries.
• Avoidable revisits: additional visits attributed to a recorded, preventable cause.
• Approval time: elapsed days from evidence submission to a decision, tracked separately from invoice-to-payment time.

Turn them into money with your own rates: query hours multiplied by staff cost, avoidable revisits multiplied by their incremental cost, and the cash tied up for the extra days multiplied by your cost of funding. Count only attributable changes and avoid counting the same job twice.

How to reduce it

• Agree what proof is needed before the job starts: scope, acceptance criteria, rates and who can approve changes.
• Capture evidence as the work happens, against those criteria, with time, location and sign-off.
• Keep changes and their approval on the job, not in email.
• Accept or raise a specific exception, so the decision is recorded.
• Connect acceptance to the invoice, so finance checks the same facts operations accepted.

The aim is proportionate evidence: enough to support a sound decision, without creating administration for the team doing the work. A clear record is proof of delivery, not paperwork.

How FortyFive narrows the gap

FortyFive keeps the record and the work together. Requirements and runbooks are set before the job, engineers capture evidence on site against them, managers approve changes in context and acceptance flows into the invoice. See how a job moves through FortyFive.

Sources

• FortyFive, The cost of unproven work, white paper, 2026.
• Service Council, Field Service Efficiency: Strategies for Improvement, 2013: 77% first-time fix rate across 226 respondents (a historical benchmark).
• Project Management Institute, Pulse of the Profession 2018: 52% of completed projects experienced scope creep or uncontrolled changes.