Decision Half Life

Not all decisions retain their value indefinitely.

Some decisions remain stable for years. Others become obsolete within days.

A Decision Half Life describes how long a decision remains valid before its usefulness begins to decay.

The decay problem

Organisations often treat decisions as permanent.

Architecture choices persist long after constraints have changed. Process decisions remain even when the system has evolved beyond them.

The result is predictable.

Outdated decisions continue to shape behaviour.

Teams optimise for conditions that no longer exist.

The system begins operating against its own history.

Different decisions decay at different rates.

Operational decisions decay quickly. Tactical decisions decay over weeks or months. Strategic decisions may persist for years.

Problems arise when these are treated uniformly.

Fast-decay decisions become bottlenecks when preserved too long. Slow-decay decisions create instability when revisited too frequently.

Each decision type requires a matching temporal model.

When decay is ignored several patterns appear.

Teams repeatedly question old decisions. Workarounds accumulate around outdated constraints. Authority becomes defensive rather than adaptive.

The organisation begins to carry historical weight.

Past decisions start competing with present reality.

Healthy systems recognise decay explicitly.

Decisions include an expected lifespan. Review points are defined at creation time. Reversal or renewal becomes routine rather than exceptional.

This does not introduce instability.

It removes the illusion of permanence.

A decision system is not static.

It is a continuously evolving structure shaped by time.

Understanding half life allows organisations to treat decisions as temporal objects rather than fixed truths.

Decisions should expire as naturally as they are created.