No Estimates advocates claim you can manage a software development effort without estimating the cost, schedule or technical performance needed to show up with the needed capabilities, for the needed cost at the needed time to deliver the needed value for those paying for your work.
This notion ignores (it seems willfully) the principles of risk management. Risk management, as Tim Lister says
Risk management is how adults manage projects
Risk management is the basis of managing in the presence of uncertainty. Showing up late, spending more than planned on the wrong deliverable is always a risk when there is uncertainty. And of course, uncertainty comes in only two forms - reducible (Epistemic) and irreducible (Aleatory).
If there is no uncertainty, then there is no risk, and estimates are not needed, since everything - the delivery date, the cost to deliver on that date, and the deliverables for that cost on that date are deterministic.
If there is uncertainty, then risk is created. In the presence of these uncertainties the data needed to make informed decisions has probabilistic and statistical attributes and behaviours. In the presence of these behaviours, deterministic outcomes are not possible. The only way to make informed decisions for the project or product is to estimate the value of cost, schedule, and technical performance to determine what these values will be in the future or what they need to be in the future to meet the needs of those paying for the work.
Anyone suggesting that any decision about cost, schedule, or technical performance can be made in the presence of uncertainty without estimating is ignoring these principles.
No matter how estimates are made, how they are used, how they are defined or redefined, in the presence of uncertainties, estimates are mandatory.
