The Goal

Productivity is not about keeping machines busy or achieving high local efficiencies. Productivity means bringing the organization closer to its ultimate goal. For a business, the goal is simply to make money. Any action that increases profitability is productive, and any action that does not is a waste of resources.

Evaluating progress toward making money requires three specific measurements. Throughput is the rate at which the system generates money through sales. Inventory represents all the money invested in purchasing items the system intends to sell, including capital assets. Operational expense is the money spent to convert inventory into throughput. Increasing throughput while simultaneously decreasing inventory and operational expense guarantees a growing net profit.

Traditional management attempts to balance capacity exactly with market demand. This approach ignores the reality of dependent events and statistical fluctuations. When a process involves sequential steps, delays in one step cascade down the line, but speed gains do not. Because fluctuations do not average out, a perfectly balanced plant will inevitably see throughput decrease and inventory rise.

Every system has at least one constraint or bottleneck that limits its overall output. A bottleneck is any resource whose capacity is equal to or less than the demand placed upon it. Identifying this weak link is the crucial first step in improving performance. Since the constraint dictates the maximum speed of the entire operation, time lost at this specific point translates directly into lost throughput for the whole business.

Once identified, the constraint must be exploited to its absolute maximum capacity. This means ensuring the bottleneck resource is never idle and works only on immediately sellable products. No new investments are needed for this step.

Every other part of the system must then be subordinated to the constraint. Non-bottleneck resources should operate only at the pace dictated by the bottleneck. Running non-constraints at full capacity merely generates excess inventory and hides the true flow of production.

If exploiting and subordinating do not break the constraint, the organization must elevate it. This involves spending capital to increase the bottleneck's capacity, such as buying new equipment or hiring additional workers. Once the capacity of the bottleneck exceeds market demand, the constraint breaks and shifts to another part of the system.

Controlling the flow of materials requires a synchronized scheduling mechanism. The constraint acts as the drum, setting the beat and production pace for the entire facility. The rope is the communication mechanism that triggers the release of raw materials into the system exactly when the drum requires them, preventing overproduction.

To protect the drum from inevitable statistical fluctuations, a time buffer is placed immediately before it. This buffer ensures the constraint never runs out of work due to delays in upstream processes. Managing this buffer size absorbs variability and protects the delivery schedule.

Conventional cost accounting drives destructive managerial behaviors by emphasizing local efficiencies. Managers often run machines unnecessarily just to lower the average cost per unit. Activating a resource and utilizing a resource are completely different concepts. Producing parts that cannot be immediately sold only increases operating expenses and inventory without generating revenue.

Improving a system is an ongoing process that cannot stop once a single bottleneck is resolved. When a constraint breaks, a new one immediately takes its place somewhere else in the value chain. Organizations must continuously cycle back to identifying the new constraint. Allowing inertia to dictate policy means old rules will artificially constrain the newly improved system.

Focusing on constraints synergizes highly with waste reduction methodologies. While waste elimination seeks to reduce costs across the board, constraint management identifies exactly where to focus those improvement efforts for maximum financial impact. Applying process improvements directly at the bottleneck creates a virtuous cycle of increased capacity and reduced operational expense.