The 9-Box Grid Is Broken for Succession Planning

What the 9-box grid actually measures

The 9-box grid plots an employee on two axes: performance and potential. Performance is at least anchored in something observable — objectives met, review scores, delivery against a role. Potential is not. In most organisations it is a manager’s instinct about how far someone could go, recorded once a year in a calibration meeting.

That gives you a grid where one axis is evidence and the other is opinion. Then both are collapsed into a single box, and the box becomes the decision.

Why that breaks succession planning

Succession planning has to answer a specific question: if this role became vacant, who could do it, and what would they need first? A box on a grid cannot answer that, for three reasons.

• It has no idea what the role requires. “High potential” is not role-specific. Someone can be genuinely excellent and still be missing the three capabilities that the target role actually depends on.
• It hides the gap. Even when the grid identifies the right person, it tells you nothing about what to develop. There is no list of missing skills, so there is no development plan — just a name on a slide.
• It bakes in bias. Potential ratings reward visibility. People who work closely with the assessor, who present well, or who look like previous leaders drift up the grid. Quiet capability drifts down.

The result is a plan that looks rigorous and is mostly a popularity contest with a matrix drawn around it.

The alternative: succession against a competency framework

Replace the potential axis with something you can actually measure. Instead of asking “how much potential does this person have?”, define what each critical role requires and assess people against that.

• Define the role, not the box. Build a competency framework that states the capabilities and proficiency levels each critical role needs.
• Assess against evidence. Score capability from real inputs — reviews, 360 feedback, objectives, qualifications and manager assessment — rather than a single annual judgement call.
• Read the gap, not the rank. The output is a ranked shortlist per role and the specific gap for each candidate. That gap is the development plan.
• Keep it live. Capability changes as people are trained and promoted. A framework updates continuously; a grid is stale the week after the calibration meeting.

This is the difference between a talent map and a succession plan. One tells you who your managers rate. The other tells you who could step up, and what to do about the difference.

Where to go next

• Succession planning without the 9-box grid — the full method, step by step.
• Competency frameworks for succession planning — how to structure the framework itself.
• Beyond the 9-Box (webinar) — the longer session this short is drawn from.