Marketing attribution
How can a law firm tell which marketing brought in each case?
UTM tags, click IDs, tracking numbers and the "how did you hear about us?" question, how to combine them in a CRM, and what GA4 can't see.
By Santiago Alvarez, Founder, Ad Hoc Digital
Last updated
The short answer
If you read one part of this page, read this.
Combine two kinds of evidence on every lead: what your tracking recorded (UTM tags, Google's click ID, the tracking number that rang) and what the person told you when you asked how they heard about you. Store both in a source field in your CRM, then count signed cases by source.
Neither kind is enough alone. Tracking misses the person who read about you in ChatGPT and then typed your name into Google. Self-reported answers miss the person who says "Google" when they mean your Local Services ad, your search ad, your Maps listing and your website all at once.
Below: each method, what it captures and misses, a simple rule for when they disagree, what GA4 can and can't tell you, and what we report to firms each month. We work with law firms across the US and Canada, and also in Australia and the UK.
The methods
Five methods, each blind somewhere different.
No single method sees every path a client takes. The point of using several is that their blind spots don't overlap much.
| Method | What it captures | What it misses |
|---|---|---|
| UTM tags on links | Which campaign, email or profile link brought a website visit | Calls dialed straight from a listing; anyone who types your address in |
| Google's click ID | Which ad, keyword and campaign produced a click that became a lead | Anything outside Google Ads |
| Tracking numbers | Which source made the phone ring | People who call the number they found somewhere else |
| "How did you hear about us?" | What the person remembers and believes | Everything they don't remember, or describe loosely |
| CRM source field | Your combined judgment, stored with the lead | Only as good as what intake enters, every time |
The first three are automatic once set up. The fourth needs intake to ask on every call and form. The fifth is where they meet, and it's the one your reports should come from.
UTM tags and click IDs
Tag every link you control, and save the tags with the lead.
UTM tags are labels added to the end of a link. Google Analytics reads them, and a well-built form saves them into the CRM so the label stays with the person, not just the visit.
- The three you always need
Google Analytics says to always use utm_source (where it came from, such as facebook), utm_medium (the type, such as paid_social or email) and utm_campaign (the campaign name). utm_term and utm_content add the keyword and the ad.
- One spelling, lowercase
Google says the values are case-sensitive, so "Facebook" and "facebook" show as two different sources. Pick one lowercase spelling per platform and write it down.
- Where to put them
Your Facebook and Instagram ads, email newsletters, links in your social profiles and your Business Profile's website link. Google Ads clicks don't need them, because they carry Google's own click ID.
- Google's click ID
Google Ads adds a unique ID to every ad click. Our forms save it in all three forms Google uses (gclid, gbraid and wbraid), because any one lead carries only one of them, along with the five UTM fields, straight into the CRM.
A test we run before any campaign goes live: add made-up tracking text to the page address, submit a test lead, and check that the CRM record shows it. If the tags didn't arrive, the campaign doesn't start. Our landing page guide covers the rest of that launch check.
Tracking numbers
Phone calls need their own tracking, because most legal leads arrive by phone.
A UTM tag can't follow someone onto a phone line. A tracking number can: each source gets its own number, and on the website each visitor can see a different one.
When a website number swaps per visitor, the call inherits the visit's UTM tags and click ID, so a call and a form from the same ad land in the CRM with the same source. Keep your real number on your Business Profile and directory listings. Our call tracking guide covers number types and the recording laws that come with them.
Asking people
Always ask how they heard about you, and never trust the answer on its own.
Self-reported source catches what tracking can't see: word of mouth, an AI answer, a talk you gave. But people answer from memory, and memory compresses.
- Why answers mislead
"Google" can mean a Local Services ad, a search ad, the Maps listing, an organic result or an AI Overview. "A friend" often means a friend named you, and then they searched your name and clicked your ad. People name the last thing they remember, not the first thing that reached them.
- Ask with a short list
On forms, a dropdown beats a blank box. The options we recommend: Google search, Google Maps, ChatGPT or another AI assistant, Facebook, Instagram or TikTok, YouTube, a referral from a lawyer, a friend or family member, and Other. Keep "AI assistant" as its own option or you'll never see it.
- Ask on calls too
Intake asks the same question near the end of the first call and records the answer in the person's own words. "My sister used you for her divorce" tells you more than "Referral".
The CRM source field
Store the first source and the latest one, and pick one rule for reporting.
Many clients contact a firm more than once before signing. If the CRM keeps only the latest source, every case looks like it came from whatever they clicked last.
Original source never changes
Set when the contact is created, from the tracking. It answers "what brought them to us in the first place?"
Latest source updates on each new inquiry
A second call from a different ad updates it. It answers "what brought them back?"
Self-reported answer sits alongside
Free text or a dropdown value, never overwriting the tracked fields.
Report signed cases by original source
Pick one rule and keep it. We use original source for budget decisions, and look at latest source when a channel seems to be finishing work another one started.
GA4 makes the same distinction. Its traffic-source dimensions prefixed "First user" keep the source that first brought a person, while those prefixed "Session" show the source of each visit. Our CRM basics guide covers the rest of the pipeline.
What GA4 can't see
GA4 sees website visits. Most of a law firm's cases begin somewhere else.
Google Analytics is good at telling you which sources bring visits and which visits fill in a form. It can't see a call dialed from Maps, a Local Services lead, or a booking made inside a widget it can't read.
- Calls from your Business Profile or Local Services Ads never touch your website, so GA4 never sees them.
- Booking calendars embedded from another service often sit in a frame GA4 can't see into. When we audited our own site, that's exactly what we found: GA4 could see page views but not which visits booked a call.
- GA4's attribution models leave out direct visits unless the whole path was direct, so a person who typed your address after hearing your name gets credited to whatever else they clicked.
- Key events are credited within a lookback window, 90 days by default. A person who first visited five months before filling in your form is outside it.
- Visits from ChatGPT, Gemini, Copilot and similar tools now fall into GA4's own AI Assistant channel. Clicks from Google's AI Overviews and AI Mode count as Organic Search.
So use GA4 for the website's share of the story, and the CRM for the case. Our guide to measuring AI search traffic covers the AI channel in detail.
What we report
What we report to firms: leads, consultations and signed cases by source, with the gaps named.
A monthly report should answer one question: where did this month's clients come from, and what did each source cost? Everything else is supporting detail.
- Tracked sources first
Paid channels with their spend, leads, good leads, consultations and signed cases, side by side. Our cost per signed case guide explains the math.
- Self-reported next to it
What people said, especially referrals and AI tools, because those don't show up in tracking. We label these numbers as a floor, not a total.
- The gaps named plainly
Leads with no source, calls nobody marked, and signed cases with no recorded outcome. A shrinking unknown pile is how you know attribution is getting better.
Tracking by source is what makes results like these visible. A boutique tax firm we built from the ground up now gets more cases from referrals than from the ads we run. For a different family law firm, almost all intake now comes from Instagram and TikTok. And one family law firm showing up first in ChatGPT has added 50 to 100 calls a month over the last three months. More on those practices on our tax law marketing and family law marketing pages.
This week
Five changes that improve attribution within a week.
None of these need new software if you already have a CRM and a website you can edit.
Add the question to every form
A required dropdown with an AI assistant option, plus a script line for intake calls.
Tag your owned links
Business Profile website link, social profile links, newsletter links. Lowercase, one spelling per platform.
Check that forms save the tags
Visit your site with a tagged link, submit a test, and look for the tags on the CRM record.
Load your site and look at the phone number
If it never changes from your real number, calls from the site are untracked.
Clean up the unknowns
Go through last month's leads with no source and fill in what you can. Then fix whichever form or line they came through.
Our systems work builds this end to end, from tracking numbers and form fields to the monthly report, and the firm owns all of it.
Common mistakes
Where firms go wrong.
The attribution mistakes we see most in the reports firms bring us.
Trusting GA4 for case counts
GA4 doesn't see calls from Maps or Local Services Ads, and it doesn't know who signed. Case counts come from the CRM.
Three spellings of one source
Google Analytics treats tag values as case-sensitive, so "Facebook", "facebook" and "FB" become three rows. Pick one lowercase spelling per platform.
Letting the latest source overwrite the first
Every case starts to look like it came from your brand search ad. Keep the original source fixed.
Treating "Google" as a source
It covers at least five different things. Use tracking to split it, and ask a follow-up question on calls.
Changing the reporting rule mid-year
Switching from first to last touch in June makes the first half of the year incomparable with the second.
Real results
What this looked like for real firms.
Three firms where knowing the source shaped the plan: a tax boutique where referrals overtook ads, a family firm whose intake comes almost entirely from Instagram and TikTok, and a family firm adding calls from ChatGPT.
Identifying details are anonymized to protect our clients. Individual result, not a promise or prediction of any specific outcome for your firm.
FAQ
Questions lawyers ask us.
Straight answers to the questions that come up most.
What is marketing attribution for a law firm?
It's working out which marketing brought in each lead and each signed case. For law firms it means combining website tracking, call tracking and the answer to "how did you hear about us?" in one CRM record, then counting signed cases by source.
Is "how did you hear about us?" reliable?
Not on its own. People name what they remember last, and "Google" covers several different things. It's still essential, because it's the only way to see referrals, AI answers and word of mouth. Keep it next to tracked data rather than instead of it.
Should we use first touch or last touch?
Store both, report on one. We use the original source for budget decisions, because it shows what brought people to the firm in the first place. The latest source shows what brought them back, which helps judge brand and retargeting campaigns.
Can Google Analytics tell us which cases came from which channel?
It can tell you which channels brought website visits and form fills. It can't see calls from your Business Profile or Local Services Ads, or know who signed. Count cases in the CRM and use GA4 for the website's part.
How do we track referrals from other lawyers?
Ask every new contact, and give referral sources their own dropdown option. Record the referring lawyer's name in the CRM. Our corporate law referral partners case study shows what a referral-first strategy can produce: six referral partners in six months.
How do we track clients who found us through ChatGPT?
Visits that click through land in GA4's AI Assistant channel. Many people don't click: they read your name and then search for you or call. So add an AI assistant option to your how-did-you-hear question. Our AI search service measures it from both sides.
Can you set up attribution for our firm?
Yes. We set up tracking numbers, tagged links, form fields and CRM source fields, and report signed cases by source every month. Schedule a consultation and we'll look at what your current reports can and can't see.
Where we do this
The services this guide touches.
What this looks like when we run it for a firm, with a demo for your practice on each page.
Sources
Where these facts come from.
Official pages we read when writing this page. Platforms and rules change, so check the current version before you act on any of it. This is marketing guidance, not legal advice.
- Google Analytics Help, URL builders: Collect campaign data with custom URLs
- Google Analytics Help, Scopes of traffic-source dimensions
- Google Analytics Help, Get started with attribution
- Google Analytics Help, Select attribution settings
- Google Analytics Help, Default channel group
- Google Ads Help, About offline conversion imports
- Google Ads Help, About call reporting
Written by
Founder of Ad Hoc Digital. Leads strategy and works directly with every client firm on AI search, Local Services Ads, Google Ads and Meta ads.
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