System change is not an excuse to avoid a difficult people decision; it is the discipline of locating the cause before making one.
Why it matters when the plan changes
Replacing a person is visible, decisive and satisfies the pressure to act. It is also the most expensive and least reversible move available, and it resolves nothing if the cause was a mandate that never matched the demand. Cross-unit commitments are the least reliable part of execution, and a slow decision often originates there rather than in the individual. The organisation then repeats the appointment and the outcome with a different name.
The tension runs both ways. A bias toward restructuring becomes a way of avoiding a decision the evidence supports, and endless system tinkering around someone who genuinely cannot carry a role is its own failure of nerve. A fit score describes the pair, not the person alone, so it cannot by itself establish that the person is the variable to change. The discipline is locating the cause first, then choosing on the merits.
In practice
A regional lead is slow to decide under a new operating model. Before any conversation about the person, four questions are asked: is the priority clear, does support exist, is the sequence achievable, does the decision sit with the right person. Three of the four turn out untested, and what looked like a replacement is a reassignment.
Evidence
Cross-unit commitments are the least reliable part of execution, which is where a slow decision usually originates rather than in the individual.
Donald Sull, Rebecca Homkes and Charles Sull, Why Strategy Execution Unravels and What to Do About It, Harvard Business Review (2015)Fit is a property of the pair rather than the person, so a score alone does not establish that the person is the variable to change.
Predictive validity, Wikipedia (2026)
What it cannot tell you
The ladder tells you which intervention to test first, not which one will work. It cannot diagnose the cause on its own; that requires evidence about the mandate, the support and the sequence. Where that evidence is absent or contested, the choice between restructuring and replacing remains a judgement, not a formula.
Questions
Is the priority clear, does the support exist, is the sequence achievable, and does the decision sit with the right person. On the support question, Harvard Business Review (2015) found only 9% of managers say they can rely on colleagues in other functions and units all the time, which is often the real point of failure.
In the short term usually, in the long term not always. Repeated structural adjustment around someone who cannot carry a role costs the organisation time, credibility and the patience of everyone working alongside them. Cheapness is a reason to test first, not a reason to stop there.
When the demand is unambiguous, the arrangement has been addressed, and the evidence still shows the person cannot carry what the role requires. That is a real finding and acting on it is not a failure of the structural approach; avoiding it would be.
One that names which rung it sits on, says why that rung should be tested first, and keeps the others visible. A recommendation that offers only one option has either done the analysis and not shown it, or has not done it.
Replacement is visible, decisive and satisfies pressure to act, while structural causes sit between roles where nobody is measured. It is also easy to justify with a single fit score, though predictive validity, as described on Wikipedia (2026), is a property of the pair, not proof the person is the variable to change.