Institutional standards erode through the gradual normalisation of departures that, accumulated, represent failures that would have been unacceptable at the beginning.
How Normalisation Works
Normalisation of drift is the process by which departures from established institutional standards are accepted as normal operating conditions rather than as deviations requiring correction. The process is incremental: each individual departure is small enough to be rationalised as an exception, an adaptation, or an acceptable response to specific circumstances. The accumulation of exceptions — each individually rationalised — produces a new operating baseline that has drifted significantly from the original standard, without any single decision having been made to accept the drift.
The NASA sociologist Diane Vaughan identified normalisation of drift as a primary cause of the Challenger and Columbia disasters: the engineering anomalies that preceded the disasters had been observed, assessed, and over successive missions rationalised as acceptable rather than as evidence of a developing failure. Each successive normalisation made the next one easier, because the new baseline was lower than the previous one. By the time the catastrophic failure arrived, the conditions that produced it had been normalised through a sequence of small acceptances that individually appeared defensible.
The Ratchet Mechanism
Normalisation of drift operates through a ratchet mechanism: departures from standard are absorbed into the new baseline but are not reversed when conditions improve. The institution that accepts a lower performance standard during a period of resource constraint does not automatically return to the prior standard when resources are restored — the new standard has been internalised, and restoring the prior standard requires deliberate action rather than simply removing the constraint that produced the departure.
This ratchet dynamic means that the normalisation of drift is effectively irreversible without deliberate intervention: each accepted departure makes subsequent departures more likely, because they are assessed against the already-drifted baseline rather than the original standard. Reversing the drift requires not just addressing the current departure but recognising that the current baseline is itself a departure from the standard that the institution should be holding itself to.
The organisation that has normalised its drift does not know it has drifted — because it has adjusted its sense of normal to match where it has arrived. Detecting the drift requires measuring against the original standard, not against where you were last year.
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