The HR Operating Model: From Ulrich's Three-Box to the Modern Stack

Almost every conversation about how to structure a People function eventually reaches Dave Ulrich's three-box model: HR Business Partners embedded with the business, Centers of Excellence holding specialist depth, and Shared Services handling transactional scale. It is the most influential HR operating model of the last 30 years — and the most commonly cargo-culted by companies who copy the structure long before they have the scale to justify it.

Ulrich's original design

Dave Ulrich's Human Resource Champions (1997) proposed that HR had to operate in four roles simultaneously: Strategic Partner, Administrative Expert, Employee Champion, and Change Agent. The three-box model that followed was the structural answer: split those roles across distinct teams so each could be done well.

What changed in the 2010s

Three forces reshaped Ulrich's model in practice: (1) HRIS automation absorbed much of what shared services used to do, (2) tech companies pioneered the 'People Operations' brand that blurred HRBP and operations into one cross-functional team, and (3) the rise of HR analytics created a fourth function that didn't fit cleanly into any of Ulrich's boxes.

The modern HR operating stack

Sizing by company stage

Common operating-model failures

• Copying Ulrich at 200 employees — splits the team before the scale justifies the overhead.
• Hiring senior HRBPs without backing CoEs — they have no specialist support to pull from.
• Letting Talent Acquisition operate as a silo with no Talent Management connection.
• Building Shared Services that automation now handles — overhead without value.
• Skipping People Analytics — flying blind on the function's own performance.
• DEI as a standalone team with no operating power — symbol without leverage.
• Confusing HRBPs with employee-relations case managers — burns out both functions.

Frequently asked questions

When should we hire our first dedicated HR person?

Typically between 40 and 80 employees, sometimes earlier with rapid growth or international expansion. The signal is when you can list five HR problems you're losing sleep over — that's the indicator that founder time spent on HR is now scaling badly.

Should our first hire be an HRBP or a People Ops generalist?

Almost always a generalist with operator instincts — someone who can stand up onboarding, fix payroll, run the first engagement survey, and coach managers, all in their first six months. Specialists come later; the first hire has to do everything.

Is the HRBP role being replaced by AI?

Parts of the HRBP role are being automated — case routing, basic policy questions, standard reporting. The strategic-advisory and judgment-heavy parts of the role are if anything more valuable, because the volume of decisions HRBPs are pulled into is increasing. The skill mix is shifting toward analytics, business context, and influence.

What's the difference between People Ops and HR?

Mostly branding. 'People Ops' originated at Google and tech companies in the 2010s and signals a more data-driven, less policy-driven stance. Functionally, modern HR and modern People Ops do the same work; the name primarily signals a cultural posture to candidates and employees.

Where does payroll sit?

Splits roughly 50/50 between Finance and People. Modern best practice: payroll execution sits with Finance, payroll policy sits with Total Rewards inside People. Outsourcing to a payroll provider is common at all stages.

Where to read further