The CFO’s Guide to Marketing Spend in Professional Services
How CFOs evaluate marketing and business development spend in law firms and B2B services: cost per signed client, payback and channel attribution.
Global Growth Playbooks · Part 25 · US · UK · Australia · Canada
The answer
CFOs struggle to evaluate marketing because spend is reported in clicks and leads while revenue is reported in signed matters and collected fees. Connect the two with three numbers: cost per signed client by channel, payback period on that cost, and collected revenue per client over twelve months. Fund the channels that pay back fastest and cut the rest.
The three numbers
| Number | Formula | Decision it supports |
|---|---|---|
| Cost per signed client | Channel spend divided by clients signed from that channel | Which channels are efficient |
| Payback period | Cost per signed client divided by average monthly gross margin per client | How quickly spend returns cash |
| Twelve-month collected revenue per client | Fees collected from clients signed in a period | Whether channels bring valuable clients, not just many |
Making attribution work
- Ask every new client how they found you and record it at intake.
- Use call tracking and form source tags for digital channels.
- Record referral sources by name.
- Reconcile sources to collected revenue, not to leads.
- Review quarterly; some channels, such as referrals and content, take months to show results.
Common traps
- Judging channels on cost per lead when lead quality differs widely.
- Cutting long-term channels (content, AI search visibility, referrals) because they do not pay back in one quarter.
- Ignoring intake conversion: a channel can look poor because inquiries are not answered.
Guardrails
- Use collected revenue, not billed, for payback.
- Agree definitions with the marketing lead before the first review.
What to measure
- Cost per signed client by channel.
- Payback period by channel.
- Share of revenue from untracked sources (aim to reduce it).
30-day checklist
- Add a source question to intake
- Pull six months of spend by channel
- Match signed clients to sources
- Calculate payback for each channel
- Present a reallocation proposal
Want help putting this in place?
Book a 15-minute call with Sagar Pratap Singh, Founder and Host of WhoBringsTheBusiness, at sagar@whobringsthebusiness.com or pick a time online. Mention this playbook and I will come prepared with a starting point for your business. Implementation is delivered through Dizital Connect.
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Next in the series: Part 26: AI Search Visibility Across Four Markets: Getting Cited by ChatGPT and Google AI
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