# Just-in-Time

**URL:** https://kaizumi.com/dictionary/just-in-time

**Description:** Just-in-Time (JIT) is a production strategy that produces only what is needed, when it is needed, in the amount needed.

**Category:** lean-principles

**Tags:** flow, foundational

## Definition

Just-in-Time (JIT) is one of the two pillars of the Toyota Production System (alongside jidoka) and represents a fundamental shift from traditional batch-and-queue manufacturing to flow-based production. JIT means producing and delivering the right items, in the right quantity, at exactly the right time. Rather than building inventory "just in case" it might be needed, JIT systems build to actual demand, dramatically reducing waste from overproduction, inventory, and the problems that inventory hides. JIT requires exceptional process reliability, quality, and coordination because there is no buffer inventory to absorb variation.

## Examples

### Manufacturing

> An automotive assembly plant receives seats from a supplier in exact sequence, delivered to the line within two hours of installation. Each seat is built specifically for the vehicle it will be installed in, matching color, features, and options. This JIT system eliminates the warehouse space that batch delivery would require.

### Healthcare

> A hospital pharmacy implemented JIT principles for IV medication preparation. Rather than batching IV preparations that might expire unused, they prepare medications within one hour of scheduled administration. This reduced waste from expired medications by 65% while ensuring fresher preparations.

### Administrative

> A loan processing center shifted from batching applications to processing each application as it arrived. This JIT approach reduced average processing time from five days to same-day, as applications no longer waited in queues between departments.

## Key Points

- JIT is demand-driven, producing to actual customer need rather than forecast
- Requires stability, quality, and reliability—JIT exposes every problem
- Small lot sizes and frequent deliveries replace large batches and warehouses
- JIT applies to information flow as well as material flow

## Common Misconceptions

**JIT means zero inventory.** JIT reduces inventory dramatically but doesn't eliminate it entirely. Strategic buffers exist where variation cannot be eliminated, and finished goods inventory may be needed to handle demand fluctuation.

**JIT is risky because there's no safety stock.** JIT actually reduces risk by making problems visible immediately rather than hiding them in inventory. High inventory often masks underlying problems that eventually cause bigger disruptions.

## Play It

Feel JIT in action: **Flow Pro** runs the same line in batches, then one piece at a time — watch lead time collapse when work flows instead of waiting in piles.

<!--GAME:flow-pro-->

## See Also

- [Pull System](/dictionary/pull-system) - The mechanism that enables JIT

Source: https://kaizumi.com/dictionary/just-in-time
Licence: free to quote and cite with attribution to Kaizumi.