DEFINITION: The phrase “just-in-time” refers to an approach to the management of supply chains which minimizes the time that supplies need to be held in inventory waiting to be used or delivered.

More specifically, “just-in-time” means synchronizing the delivery of raw materials or intermediate products received from suppliers with production schedules, or else the delivery of finished products from wholesalers with customer delivery schedules, as the case may be.

The idea is that supplies should arrive “just in time” to be used or delivered, minimizing the need to store them on site.

ETYMOLOGY: The concept of “just-in-time” is usually held to have been invented by the Toyota company in Japan in the 1970s.

The English adverb “just” derives, via Middle English, from the Middle French adjective juste and the Latin adjective iustus, meaning “just,” “equitable,” or “fair,” which, in turn, is derived from the noun iūs, iūris, meaning “right” or “law.”

The English preposition “in” derives from identical forms in Middle English and Old English; the latter is akin to identical forms in Old High German and in Latin.

The English noun “time” derives, via Middle English, from the Old English word tīma, with the same meaning. It is akin to Old Norse tīmi, also with the same meaning.

USAGE: The just-in-time inventory system—sometimes abbreviated as “JIT”—serves to reduce inventory levels while enhancing operational efficiency.

Since JIT production systems procure materials and components only as required for production, they reduce the need for holding large amounts of inventory, thus minimizing or even eliminating the need for on-site storage of supplies, thus minimizing the expenses associated with inventory storage.

Additionally, JIT reduces the danger of manufacturers’ being stuck with surplus inventory if orders are canceled.

A prime illustration of the JIT inventory system is evident in the case of automobile manufacturing—the very industry which first developed the concept.

Auto manufacturers typically maintains minimal inventory levels, thus relying heavily on their supply chains to provide parts they require on a need-based schedule.

Consequently, an auto manufacturer typically places orders for essential vehicle components only after receiving order from their customers.

For JIT manufacturing to be implemented successfully, a number of requirements must be fulfilled: notably, dependable suppliers, consistent production, flawless functioning of plant machinery, and exceptional craftsmanship.