// glossary

Glossary

The terms the writing here coined or uses in its own sense, one sentence each, linked to the page that is the source. The Lab's own vocabulary - Intelligent Orchestration, OODAA, the projects - is in the Lab's glossary.

Asymmetric supply chain: An asymmetric supply chain has a funnel shape - a fragmented base of artisanal producers and small enterprises, market access and value controlled in the mid-section, capital and data at the neck. There is nothing to adjust around a shock, so it travels up the funnel to the market and back down to the base, which absorbs it. In the research literature the same phrase usually means relational, informational or dependence asymmetry between trading parties; the sense used here is structural - the shape of the network and where the variance enters it. Read heuristic 02.
Heuristics: Heuristics is the author's series of one-page rules for operations and supply chain, each carrying a problem, a rule, a test, a real case, the mistakes and a maxim. Read the series.
Hybrid supply chain: A hybrid supply chain is brand-centred and layered - asymmetric upstream, symmetric downstream. Brand owner and contract manufacturers absorb different halves of a shock by contractual arrangement, and the model restores itself only while neither half exceeds what it was designed to carry. Distinct from the common usage, where a hybrid operating model means centralised functions combined with decentralised ones; that is a question of who reports to whom, this is a question of which physics each end of the chain runs on. Read heuristic 02.
Idealised Supply Chain Design: Idealised Supply Chain Design is a design method that abstracts a supply chain problem to the function it has to perform, then moves the system toward the ideal of performing that function with no system at all. See the series.
Outside Variance Ratio (OVR): The Outside Variance Ratio, or OVR, is the share of an operation's total variance that originates outside the company's walls - sigma squared (outside) divided by sigma squared (total). A low OVR indicates symmetric physics; asymmetry appears as OVR rises. It is ordinal in practice, a field estimate rather than a figure measured to two decimals, and it is the quantitative form of the third question in the heuristic 02 test. Read heuristic 02.
Requisite variety in supply chain: Requisite variety in the supply chain is the rule that any department can control only as much variation as it can absorb, and everything beyond that brings costs, delays or constant troubleshooting. Stated formally as Vr >= Ve - the distinct actions an operation can take in a time step against the distinct situations it faces - after W. Ross Ashby. Read heuristic 01.
Symmetric supply chain: A symmetric supply chain is interdependent and balanced - partners share information, decision rights, risk and sometimes assets, so when an external factor hits one node the whole ecosystem adjusts to restore inventory and capacity to homeostasis. Read heuristic 02.
Variety Shortfall Test: The Variety Shortfall Test takes the operational problem that keeps coming back and asks which of four layers is short - you cannot see it, you can see it but cannot act, you can act only one way, or the right action lands too late. The short layer is the one to fix, not the noisiest one. Read heuristic 01.