Which practice areas should a firm advertise?

Practice-area allocation is usually settled with two inputs: cost per lead by area, and a partner's sense of which matters were pleasant to run. The second is doing more work than anyone admits, and the first is actively misleading, because cost per lead and value per matter tend to move in opposite directions. Areas with high matter values attract more competition and cost more to advertise into; areas with low matter values are cheap precisely because fewer firms want them.

The consequence is not a bad quarter. It is drift. A firm that allocates on cost per lead each quarter, and reallocates toward whatever performed well on that metric, will over a few years find its case mix has shifted toward high-volume, low-value work — without any single decision to become that firm ever having been taken. Each individual reallocation looked efficient in isolation.

The unit that resists the drift is profit per fee-earner hour by practice area, and it is more obtainable than it sounds. Firms already record time and already know what they billed and collected. What is usually missing is the join between acquisition spend and the matter it produced, which requires source tagging at enquiry and nothing else. With that join, each area can be ranked on what it actually contributes per hour of the capacity it consumes, which is the constraint that matters.

Two adjustments make the ranking honest. First, realisation: a matter billed is not a matter collected, and areas differ substantially in write-offs and in how much of the recorded time survives to an invoice. Second, cycle length: an area whose matters sign quickly returns capital faster than one whose matters take three quarters to sign, and a firm managing cash cannot rank the two purely on eventual margin. Both adjustments are available in the firm's own accounting and neither typically appears in a marketing discussion.

There is a constraint that sits outside the arithmetic and can veto it. Advertising by practice area is governed by state rules on lawyer advertising and specialisation, and describing the firm or its lawyers as specialists or experts in an area is restricted in many jurisdictions unless a recognised certification applies. That is a rule about how an area may be advertised rather than whether, but it changes the creative, the landing page and sometimes the viability of the channel, and it is cheaper to establish before the budget is committed.

The allocation that comes out of this is usually more concentrated than the one it replaces. Ranked by profit per hour and adjusted for realisation and cycle, most firms find a small number of areas carrying the return, and the honest move is to fund those properly rather than spread thinly across everything the firm is capable of doing. Breadth is a capability statement; it is not an advertising strategy.