Jessica Grubbs · Analytics & Measurement Engineer

The investigation is the product

I got my start in the Coast Guard, working on electrical and infrastructure systems, where guessing isn't an option. Now I'm a conversion tracking and tagging engineer, which means I build tracking systems that work: server-side GTM, GA4, Consent Mode, BigQuery, Python. The part I like is the detective work. Tracking rarely breaks in an obvious way. It breaks quietly, everything looks fine, and then the numbers don't line up.

Anyone can generate a polished case study now. These three show the harder part: how I work a broken system, including where I guessed wrong.

Case studies

01Investigation

The Consent Gap

A European outdoor retailer on Shopify Plus was doing roughly 100k EUR a month in orders. GA4 saw about 8k. Around 91% of the revenue was invisible, and both vendors' dashboards said everything was fine. The failure lived in the handshake between two systems, not inside either one.

Read the investigation →

02Build

Greenfield Tracking Build

A SaaS product with zero analytics. No property, no containers, nothing. Building the full measurement layer from empty, alongside a colleague's work without touching it, plus the verification steps that aren't in any docs.

Read the build →

03Build

The Five-Domain Dashboard

A five-domain SEO dashboard built from an empty report. The easy half was building it. The hard half was proving every number matched a baseline the client already trusted, before handing it over.

Read the build →

How I work

Instrument before you conclude.

If the test setup is contaminated, every finding is fiction. I verify the instrument first.

AI is part of my toolkit, and so is not trusting it.

I run agent-assisted investigations daily. My job is catching what the tools get wrong: the fabricated field, the misread metric, the confident wrong answer.

Fix the class of problem, not just the problem.

Durable credentials, documented gotchas, handoff notes for the next person.

Get in touch

Email is the fastest way to reach me. Resume and profiles below.

Email Resume (PDF) LinkedIn GitHub