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Law Firm WIP: Turning Unbilled Time Into Cash
Work in progress is the least visible asset in the firm. It does not appear on collection reports and it does not trigger a dunning workflow — it simply ages, and loses value while it does.
What We Do
WIP is inventory. And inventory decays.
Law firm WIP (work in progress) is time that has been recorded but not yet invoiced. It behaves like inventory: it sits on the books at full stated value, it decays as it ages, and past roughly 90 days it becomes materially harder to bill without a write-down.
If you measure one thing after reading this page, measure your WIP aging.
Unbilled time is technically an asset. It is on the books. It has a stated value. But unlike a receivable, nothing in the firm’s operating rhythm forces anyone to look at it. Receivables have aging reports, owners and escalation paths. WIP usually has none of the three.
So it ages quietly — and the older it gets, the harder it becomes to bill at full value and the easier it becomes to write down without anyone making a deliberate decision.
How It Happens
The write-down nobody actually decided to make.
The mechanism is entirely mundane, which is exactly why it persists.
A matter wraps up. Three months of accumulated time lands on a single pre-bill. The billing partner sees one large number instead of three timely ones and discounts it — partly to pre-empt client pushback, partly because at this distance even they can no longer reconstruct what every entry was for. The write-down feels prudent. In isolation, it is.
“Nobody decides to write off ten percent of the firm’s work. It happens one aged pre-bill at a time.”
Repeated across every matter in the firm, those individually sensible decisions become a structural tax on revenue — one that never appears as a line item anywhere.
What We Measure
Four drivers that determine how fast WIP converts.
Aged WIP is a symptom. These four are the causes, and each one is measurable with data the firm already has.
The Capture Gap
The elapsed days between doing the work and recording it. Reconstructed time is undercounted time, and this loss never enters the system at all — which makes it invisible to every downstream report.
Pre-Bill Latency
How long a pre-bill waits between generation and partner review. This is usually the single largest controllable component of lock-up, and it is almost never measured.
Billing Cadence
Long-running matters billed “at a natural point” rather than monthly. Natural points arrive late and irregularly, which is what allows WIP to accumulate into one intimidating number.
Ownership
Whether any named individual is accountable for WIP over 90 days. In most firms the honest answer is no — and unowned inventory does not move.
The Approach
DMAIC, applied to unbilled time.
The same five-phase method we apply to any recurring process problem — here pointed at the inventory sitting in your practice management system.
Define
Establish what WIP actually costs this firm — aged balances by partner and practice group, realistic realization on aged versus current pre-bills, and the resulting drag on lock-up.
Measure
Instrument the capture gap and pre-bill latency. Most firms already hold this data; it has simply never been reported in a form anyone is accountable for acting on.
Analyze
Separate structural causes from individual behaviour. A partner who bills late every month is a different problem from a matter type whose scope makes timely billing genuinely hard.
Improve
Standard pre-bill timing, monthly billing triggers for long-running matters, and aging visible at the level where someone can act on it.
Control
A standing WIP review with a named owner and a defined threshold — so the improvement survives a busy quarter rather than decaying with the next one.
The Result
More of the work already performed gets billed at full value. Not by working more hours — by losing fewer of the ones already worked.
Common Questions
Questions we hear about law firm WIP.
What does WIP mean in a law firm?
WIP — work in progress — is time that attorneys have recorded but the firm has not yet invoiced. It sits between time capture and billing in the revenue cycle, and it is the stage where value is most commonly lost without any deliberate decision being made.
Why does aged WIP get written down?
Two reasons compound. Large accumulated pre-bills invite discounting because the total looks alarming next to a single month of work. And at distance, the narrative detail supporting each entry becomes harder to defend — so the safest path is to reduce it.
What is a reasonable WIP aging threshold?
Ninety days is the point at which most firms see collectability begin to slide measurably. The more useful question is not the threshold itself but whether anyone is accountable when WIP crosses it. A threshold nobody owns is a number, not a control.
Is this a software problem?
Rarely. Most practice management systems can already report WIP aging. The gap is almost always that the report is not produced on a cadence, not routed to someone accountable, and not attached to a defined action when a threshold is breached.
How does WIP relate to lock-up?
Lock-up is the total elapsed time from work performed to cash collected, and WIP is usually its largest and most controllable component. Firms chasing lock-up through collections alone are optimising the shorter half of the problem. See revenue cycle management for law firms.
How old is your unbilled time?
If you cannot answer that in under a minute, that is the finding. Tell us what your system reports and we will tell you what it is costing.
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