Goldratt's Theory of Constraints: What It Means for Office and Sales

Why improvements in the office so often fizzle out

Many companies improve constantly. Accounting gets new software, sales gets a template for first meetings, order processing gets a new form. Each measure saves time somewhere. And yet no more orders come out at the end of the month, and delivery times stay as they were.

Eliyahu Goldratt offered an explanation for this pattern that is known as the theory of constraints. It comes from the factory. In the office it is applied less often, although the workflows are built in a similar way: a chain of stations at which work waits.

This article therefore asks: what is the theory of constraints worth for the office and sales work of a small company, and where does it lead you astray? To answer, we first clarify the terms, then explain the thinking model of the five focusing steps, examine the research findings, weigh the theory of constraints against lean, and finally derive how to apply it.

An hour lost at the constraint is lost for the whole company. An hour gained elsewhere is often just one more hour of waiting.

What is the theory of constraints? Terms and origins

The theory of constraints goes back to the Israeli physicist Eliyahu M. Goldratt. It became known in 1984 through the novel The Goal (Goldratt and Cox 1984), in which a plant manager saves his factory from closure. A constraint, or bottleneck, is the point in a workflow that limits the throughput of the whole at a given time. Throughput is what the workflow produces at the end. In sales that is orders per month, in order processing completed deliveries.

Goldratt added three measures. Throughput in the financial sense is revenue minus truly variable costs, usually just materials. Inventory is all the money tied up in the system. Operating expense is all the money spent to turn inventory into throughput. Why this accounting reaches the same result as the relative contribution margin when applied correctly is described in the article on contribution margin per order.

In the novel, Goldratt explains the principle with a hike. A group of scouts moves only as fast as its slowest member. The solution in the book is to put the slowest at the front and take part of his pack off him. The same holds in the office: the speed of a workflow is set by its slowest station, not by the average of all stations.

The thinking model: five focusing steps and drum, buffer, rope

The core of the theory of constraints is made up of five focusing steps. They are not a one-time instruction but a loop that starts again after each pass. In his review of the literature on the theory of constraints, Rahman (1998) describes exactly this idea of ongoing improvement as its underlying philosophy, supplemented by a set of thinking tools for root-cause analysis that Goldratt called the thinking processes.

1. Identify the constraint

   Look for the station where work piles up and whose output limits the result. In sales, the three-value check of volume, rate, and waiting time does this.

2. Exploit the constraint

   Get out of the station whatever is possible with existing means. The constraint works only on things that only it can do and never waits for documents.

3. Subordinate everything else

   The other stations work at the pace of the constraint. Producing more in advance than the constraint can process only builds piles.

4. Elevate the constraint

   Only now do investments come into question: a second person, a tool, training.

5. Start over

   Once the constraint is resolved, it moves elsewhere. Goldratt explicitly warns that the rules that applied to the old constraint then become an obstacle themselves.

For day-to-day control, Goldratt coined a second image: drum, buffer, rope. The drum is the constraint that sets the pace. The buffer is a small stock of fully prepared work in front of the constraint so that it never runs empty. The rope connects the constraint with the start of the workflow: new work is accepted or triggered only to the extent that the constraint can process it.

Where is the constraint in office and sales work?

In the factory the constraint is often visible: a machine in front of which parts pile up. In the office, work piles up invisibly, in inboxes, folders, and open tasks. Goldratt therefore distinguished between physical constraints, meaning missing capacity, and policy constraints, meaning rules, habits, and metrics that slow the flow. In the office, policy constraints are more common than physical ones.

Four of five stations have reserves. Speeding up invoicing here saves time that is needed nowhere. Relieving pricing by two quotes per week raises the output of the entire workflow by a quarter. How to find the constraint in sales is described in the article on sales bottleneck analysis.

What research shows about the theory of constraints

The literature on the theory of constraints is broad but methodologically one-sided. Rahman's review (1998) already lists applications in purchasing, accounting, and administration, so the theory reached beyond the factory early on.

Datt and colleagues (2024) evaluated 36 journal articles from 1999 to 2021 that applied the theory of constraints in healthcare, a field that in many ways resembles office work: many handoffs, few machines, people as the scarce resource. Almost all documented applications reported substantial improvements. That is also a warning sign: if nearly every published application succeeds, failed attempts are probably not being published.

Gupta, Digalwar, Gupta, and Goyal (2024) examined how the theory of constraints can be combined with lean and Six Sigma. To do so, they accompanied a small Indian die-casting company. Their starting point: each of the three methods on its own often falls short of its promise, and some companies slide back into old patterns. The theory of constraints, they argue, brings one ability the others lack, namely setting the order of improvements by their effect on throughput. The tools for implementation come from lean and Six Sigma instead. According to the authors, flow and scrap improved in the company studied, and the financial figures followed. They themselves stress that this is an exploratory study in a single company.

Knop (2025) shows in a Polish machinery company that the most important constraint can also be a missing rule, in that case missing work instructions. From a short review, Kasemset (2011) concludes that studies combining the theory of constraints with other improvement methods report clearly better results.

Constraint or waste? Two perspectives

Anyone who deals with improvement in a company sooner or later meets two schools that seem to contradict each other. The first is lean, the thinking from the Toyota Production System. It looks for waste everywhere: waiting times, rework, duplicate data entry. Every station is supposed to become leaner. The second is the theory of constraints. It considers this a waste of effort as long as the constraint remains untouched, and deliberately accepts that other stations have spare time.

The first reading says: you have to choose. The second says: the two approaches answer different questions. The theory of constraints answers where to improve. Lean answers how. The findings of Gupta and colleagues and the review by Kasemset support the second reading. I also consider it the right one in practice, because it solves a typical problem of small companies: there are too many possible improvements and too little time. The types of waste described in the article on lean in the office then become not a program for the whole company but a checklist for the one station that currently sets the pace.

One limitation remains. In the office, the constraint moves faster than in the factory. Vacation or a large order shift it within days. That is why the fifth step, starting over, belongs to the regular rhythm.

How to apply the theory of constraints in the office in four weeks

You need no software, only a defined workflow, such as from inquiry to order confirmation, and four weeks of patience for a single point.

1. Week 1: make the workflow and the backlog visible

   Write down the stations and count on a set day how many items are waiting in front of each station. The station with the largest pile is the first candidate.

2. Week 1: roughly estimate capacity

   Estimate for each station how many items it handles per week. If the largest backlog coincides with the smallest capacity, you have found the constraint.

3. Week 2: exploit the constraint

   Take everything off the constraint that others can do: compiling documents, clarifying questions, coordinating appointments. Establish that items reach the constraint only when complete.

4. Week 3: set up the buffer and the rope

   Always keep two to three fully prepared items in front of the constraint. Trigger new work only as fast as the constraint can process it.

5. Week 4: measure and search again

   Compare throughput with the starting value. Check whether the backlog has shifted to another station. Then the loop starts again.

The figures continue the worked example and are freely chosen. The first gains often cost nothing but a new sequence. How much plannable time the constraint really has is shown by the method from the article on capacity planning. Anyone who runs the workflow as a board sees the backlog daily, as the article on Kanban in sales shows.

Beyond the individual case, an uncomfortable insight about metrics follows. Measuring each department by its own utilization rewards work done ahead for a constraint that cannot process it. A shared number for the whole workflow makes more sense, such as orders per week. How to bring it into a regular improvement rhythm is described in the article on process optimization step by step.

Conclusion: what is the theory of constraints worth for office and sales?

We began by asking
the theory of constraints offers a small company for its office and sales work. The answer is mixed. As a thinking model it is very useful there, because it asks the most important question first: where does the workflow limit itself? The five focusing steps and the image of drum, buffer, and rope can be transferred to quotes, approvals, and order confirmations without software. As a proven method, by contrast, it is weaker than its supporters believe, because the research consists mostly of positive single cases. It achieves the most together with the tools from lean, as a compass for the order of work. Used this way, you no longer work a little on everything, but properly on one point.

What you can put into practice right away

1. Choose a workflow that costs you revenue or delivery time, and write down its stations.
2. On a set day, count how many items are waiting in front of each station.
3. Ask yourself honestly whether the station with the largest pile is you.
4. Take one task off the constraint that someone else can also do.
5. Put a date in your calendar four weeks from now on which you count the backlog again.

The theory of constraints does not require enthusiasm for methods, only discipline.