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Why Quality Control Becomes Harder at Scale

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Why quality control becomes harder at scale: two competing explanations, sheer volume versus how the work is organised, and what each implies.

The Case That It’s a Volume and Complexity Problem

The intuitive explanation is also a defensible one: more output, more variation in how that output is produced, and more interdependent steps in producing it, simply create more surface area for defects to occur and more difficulty catching them before they matter. Jay Galbraith’s information-processing view of organisation design supports this directly — as task interdependence and volume rise, the information-processing burden on any quality system rises correspondingly, and a quality system designed for a smaller, simpler operation will structurally struggle to keep pace unless it evolves alongside the operation it is meant to monitor. On this account, quality control becomes harder at scale for essentially the same reason coordination becomes harder at scale: there is more to track, more interdependency between the parts, and less of it is directly observable to any one person.

The Case That It’s a Measurement and Feedback Problem

A different, equally well-evidenced account locates the difficulty elsewhere: not in the volume of what is being produced, but in what happens to the reliability of the measures used to monitor it. V. F. Ridgway’s research at Cornell’s Johnson Graduate School of Management found that performance and quality measures reliably produce behavioural distortion — people and teams adjust their behaviour toward what is measured, not necessarily toward the underlying outcome the measure was meant to represent. Ridgway’s own examples are instructive here: interviewers measured on volume interviewed faster and placed fewer people; investigators given a fixed monthly quota of cases selected easier cases as the deadline approached. Quality measures are exactly this kind of measure, and this account holds that quality gets harder to see, not necessarily harder to achieve, as an organisation scales — because scale typically means quality measurement becomes more indirect, more removed from direct observation, and therefore more exposed to exactly the kind of distortion Ridgway documented.

On this account, the core difficulty is not that there is intrinsically more to go wrong. It is that the people closest to the work are increasingly measured and evaluated by proxies for quality rather than by quality itself, and proxies are what get optimised under pressure — sometimes at the direct expense of the thing they were meant to represent.

Why the Disagreement Persists

Neither explanation fully displaces the other, which is why the disagreement persists rather than resolving. The volume-and-complexity account is clearly true as far as it goes — a larger, more interdependent operation genuinely does have more places for defects to originate. But it does not, on its own, explain why some large organisations sustain excellent quality while others do not, at comparable scale and complexity — a gap the measurement-and-feedback account addresses directly, by pointing to differences in how reliably quality is actually being measured and fed back to the people who can act on it.

Equally, the measurement-and-feedback account does not fully explain why quality problems specifically correlate with scale, rather than appearing at random regardless of size — a correlation the volume-and-complexity account explains more directly, since genuine complexity does rise with scale in a way that measurement distortion, in principle, does not have to.

What It Means for a Leader

The two accounts point toward different diagnostic questions, and distinguishing between them in a specific organisation is more useful than assuming one applies universally. If quality problems track closely with genuine increases in volume and interdependency — more products, more variants, more interdependent steps — the volume-and-complexity account is likely doing most of the explanatory work. If quality problems persist or worsen even where volume and complexity have been relatively stable, but the distance between where work happens and where it is measured has grown, the measurement-and-feedback account deserves closer attention. In most real organisations, both forces are present simultaneously and reinforcing each other — rising complexity increases the information-processing burden at the same time as it increases the distance between direct observation and formal measurement — which is precisely why quality control becoming harder at scale is so consistently reported and so rarely resolved by addressing only one side of it.

There is a further complication worth naming: the two forces do not just coexist, they actively reinforce each other in a way that makes the underlying problem harder to diagnose than either account alone suggests. Rising complexity creates more genuine opportunities for defects (Position A), while simultaneously stretching the distance between the work and its measurement, making those same defects harder to detect reliably (Position B). An organisation experiencing both simultaneously may see a quality metric that looks stable — because the measurement itself is degrading at roughly the rate that underlying defects are rising — right up until the gap between the two becomes large enough to surface as a visible failure, at which point it often looks sudden, even though both underlying trends had been building for some time.

A Third Consideration: Who Is Closest to the Defect

A further dimension, distinct from either the volume-and-complexity or the measurement-and-feedback account, is worth introducing directly: the physical and organisational distance between where a defect originates and where it is finally caught. In a small operation, the person best placed to notice a quality problem is often also the person doing the work — defect and detection sit close together, in time and in person. As an operation scales, these two roles frequently separate: the person producing the work and the person responsible for verifying its quality become different people, often in different parts of the organisation, sometimes separated by several intermediate steps. This separation is not itself a failure of either account examined above; it is a structural consequence of specialisation, the same dynamic Galbraith’s framework describes more generally. But it adds a genuinely distinct source of difficulty: even a perfectly designed quality measure, applied by someone with no direct exposure to the conditions under which the defect actually occurred, will tend to catch a narrower slice of what is actually going wrong than the same measure applied by someone closer to the work.

For how this pattern presents in other kinds of organisation, see other sectors.

Questions worth considering

  1. Do quality problems in this organisation track most closely with genuine increases in volume and complexity, or with growing distance between the work and how it’s measured?
  2. How direct is the current path between someone doing quality-relevant work and someone able to see the result of a quality measure based on it?
  3. Are quality metrics currently measuring the outcome that matters, or a proxy that has become easier to measure than the outcome itself?

More on this topic: Operations.

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Sources

Jay R. Galbraith, “Organization Design: An Information Processing View,” Interfaces, 4(3), 1974, pp. 28–36.

V. F. Ridgway, “Dysfunctional Consequences of Performance Measurements,” Administrative Science Quarterly, Vol. 1, No. 2 (September 1956), pp. 240–247.

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Frequently Asked Questions

Credible evidence supports both. Volume and interdependency genuinely rise with scale (Galbraith, 1974), while the reliability of quality measurement tends to degrade with distance from direct observation, and is prone to distortion (Ridgway, 1956). This article presents both without resolving which dominates in a given case.
That single, multiple, and composite measures can all produce undesirable behavioural consequences, because people optimise toward what is measured rather than the underlying outcome the measure was meant to represent.
Not necessarily, and this article does not prescribe a fix. If the underlying issue is measurement distortion rather than volume, additional checks using the same kind of proxy measure may not address the actual cause.
Yes — the distance between the person producing the work and the person verifying its quality is itself a factor. As that distance grows with scale, even a well-designed check tends to catch a narrower slice of what is actually going wrong.
The argument is that more output, more variation in how it is produced and more interdependent steps create more surface area for defects and more difficulty catching them. Galbraith’s information-processing view supports it: as interdependence and volume rise, so does the burden on any quality system, and one designed for a smaller operation structurally struggles unless it evolves alongside the operation.
When rising complexity creates more opportunities for defects while also stretching the distance between the work and its measurement, a metric can look stable because measurement is degrading at roughly the rate defects are rising. The gap eventually becomes large enough to surface as a visible failure, which often looks sudden even though both trends had been building.
Neither fully displaces the other. The volume-and-complexity account does not explain why some large organisations sustain excellent quality at comparable scale, while the measurement-and-feedback account does not fully explain why quality problems correlate with scale rather than appearing at random. Each covers a gap the other leaves, and both forces are often present and reinforcing each other.
On the measurement account, scale typically makes quality measurement more indirect, so people closest to the work are judged by proxies rather than by quality itself, and proxies are what tend to get optimised under pressure. Ridgway’s examples include interviewers measured on volume who interviewed faster and placed fewer people, and investigators on a monthly quota who chose easier cases as the deadline approached.