Zero-based budgeting works only if you know what things truly cost.
Zero-based budgeting asks every manager to justify their budget from zero, not from last year. It is a powerful idea and a famous one, and it fails more often than it should, for a single reason: most organizations have nothing solid to justify against. Without a causal view of cost, a zero base is just a blank page and a negotiation. With one, it becomes the sharpest cost discipline there is.
In short
Zero-based budgeting (ZBB), developed by Peter Pyhrr at Texas Instruments and published in Harvard Business Review in 1970, rebuilds the budget from zero each cycle, requiring every activity to be justified. Its weakness is that justification needs a true cost baseline. Time-driven activity-based costing supplies exactly that, which is why ZBB and TDABC belong together.
Zero-based budgeting rebuilds from zero; incremental budgeting builds on last year. Illustrative.
Zero-based budgeting has one of the best origin stories in management. Peter Pyhrr developed it at Texas Instruments in the late 1960s, set it out in a 1970 Harvard Business Review article, and saw it adopted first by the State of Georgia under Jimmy Carter and then, when Carter reached the White House, by the US federal government. The idea is simple and radical: instead of starting from last year and adjusting, you start from zero and make every manager justify every activity before it gets a single euro. Done well, it strips out the accumulated waste that incremental budgeting quietly protects.
Done badly, which is most of the time, it collapses into theatre. Managers are asked to justify their costs from zero, but the only cost information they have is the same historical, averaged, overhead-laden numbers that hid the waste in the first place. So they justify everything, because nothing can be confidently cut, and the exercise produces enormous effort and little change, or worse, it cuts visible muscle because the real fat is invisible. The problem was never the principle of ZBB. It was the absence of a cost model good enough to make the justification real.
- Managers justify from the same averaged numbers that hid the waste, so nothing is confidently cut.
- Effort is enormous; the resulting budget looks a lot like last year's.
- Cuts land on visible, easy targets rather than the true cost drivers.
- Indirect and shared costs cannot be challenged, because no one knows what causes them.
- The exercise is done once, declared exhausting, and quietly abandoned.
How TDABC makes ZBB work
Here is the connection that makes zero-based budgeting deliver. Time-driven activity-based costing gives you the true cost of every activity, built from the capacity it consumes, not from an average. When a manager is asked to justify an activity from zero, they are now justifying a real number, the genuine cost of doing it, against the genuine value it produces. Activities that cost more than they are worth become visible and cuttable; activities that look expensive but are essential can be defended with evidence. In effect, activity-based budgeting and zero-based budgeting converge: both build the budget from what activities truly require, one forward from the plan, the other by justifying from zero. An illustrative example: an organization running ZBB on averaged numbers cut its training budget because it was easy to see, while leaving a costly, low-value approval process untouched because no one could cost it. With a causal model, the priorities reverse. Figures and outcome illustrative; ZBB history per Pyhrr (HBR, 1970).
Zero-based budgeting is not for every cycle. It is heavy, and run annually it exhausts an organization. Use it periodically, every few years or when a real reset is needed, and run lighter activity-based budgeting in between. Either way, the prerequisite is the same: a cost model that can tell you what an activity truly costs, so the justification is real. That is where to start, and it is why ZBB sits on the same maturity ladder as everything else we do.
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