Social distancing and the Theory of Constraints


An organised queue or line1

I was listening to the BBC News the other evening. There was discussion of return to work in the construction industry. A site foreman was interviewed and he was clear in his view that work could be resumed, social distancing observed, safety protected and valuable work done.

Workplace considerations are quite different from those in my recent post in which I was speculating how an “invisible hand” might co-ordinate independently acting and relatively isolated agents who were aspiring to socially isolate. The foreman in the interview had the power to define and enforce a business process, repeatable, measurable, improvable and adaptable.

Of course, the restrictions imposed by Covid-19 will be a nuisance. But how much? To understand the real impact they may have on efficiency requires a deeper analysis of the business process. I’m sure that the foreman and his colleagues had done it.

There won’t be anyone reading this blog who hasn’t read Eliyahu Goldratt’s book, The Goal.2 The big “takeaway” of Goldratt’s book is that some of the most critical outcomes of a business process are fundamentally limited by, perhaps, a single constraint in the value chain. The constraint imposes a ceiling on sales, throughput, cash flow and profit. It has secondary effects on quality, price, fixed costs and delivery. In many manufacturing processes it will be easy to identify the constraint. It will be the machine with the big pile of work-in-progress in front of it. In more service-oriented industries, finding the constraint may require some more subtle investigation. The rate at which the constraint works determines how fast material moves through the process towards the customer.

The simple fact is that much management energy expended in “improving efficiency” has nil (positive) effect on effectiveness, efficiency or flexibility (the “3Fs”). Working furiously will not, of itself, promote the throughput of the constraint. Measures such as Overall Equipment Effectiveness (OEE) are useless and costly if applied to business steps that, themselves, are limited by the performance of a constraint that lies elsewhere.

That is the point about the construction industry, and much else. The proximity of the manual workers is not necessarily the constraint. That must be the case in many other businesses and processes.

I did a quick internet search on the Theory of Constraints and the current Covid-19 pandemic. I found only this, rather general, post by Domenico Lepore. There really wasn’t anything else on the internet that I could find. Lepore is the author of, probably, the most systematic and practical explanation of how to implement Goldratt’s theories.3 Once the constraint is identified:

  • Prioritise the constraint. Make sure it is never short of staff, inputs or consumables. Eliminate unplanned downtime by rationalising maintenance. Plan maintenance when it will cause least disruption but work on the maintenance process too. Measure OEE if you like. On the constraint.
  • Make the constraint’s performance “sufficiently regular to be predictable”.4 You can now forecast and plan. At last.
  • Improve the throughput of the constraint until it is no longer the constraint. Now there is a new constraint to attack.
  • Don’t forget to keep up the good work on the old constraint.

This is, I think, a useful approach to some Covid-19 problems. Where is the constraint? Is it physical proximity? If so, work to manage it. Is it something else? Then you are already stuck with the throughput of the constraint. Serve it in a socially-distanced way.

The court system of England and Wales

Here is a potential example that I was thinking about. Throughput in the court system of England and Wales has, since the onset of Covid-19, collapsed. Certainly in the civil courts, personal injury cases, debt recovery, commercial cases, property disputes, professional negligence claims. There has been more action in criminal and family courts, as far as I can see. Some hearings have taken place by telephone or by video but throughput has been miserable. Most civil courts remain closed other than for matters that need the urgent attention of a judge.

And that is the point of it. The judge, judicial time, is the constraint in the court system. Judgment, or at least the prospect thereof, is the principal way the courts add value. Much of civil procedure is aimed at getting the issues in a proper state for the judge to assess them efficiently and justly. The byproduct of that is that, once the parties have each clarified the issues in dispute, there may then be a window for settlement.

What has horrified the court service is the prospect of the sort of scrum of lawyers and litigants that is common in the inadequate waiting and conference facilities of most courts. That scrum is seen as important. It gives trial counsel an opportunity to review the evidence with their witnesses. It provides an opportunity for negotiation and settlement. Trial counsel will be there face to face with their clients. Offer and counter offer can pass quickly and intuitively between seasoned professionals. Into the mix are added the ushers and clerks who manage the parties securely into the court room. It is a concentrated mass of individuals, beset with frequently inadequate washing facilities.

Court rooms themselves present little problem. Most civil courts in England and Wales are embarrassingly expansive for the few people that generally attend hearings. Very commonly just the judge and two advocates. I cannot think of that many occasions when there will have been any real difficulty in keeping two metres apart.

With the judge as the constraint and the court room not, what remains is the issue of getting people into court. Why is that mass of people routinely in the waiting room? Well, to some extent it serves, in the language of Lean Production, as a “supermarket”,5 a reservoir of inputs that guarantees the judicial constraint does not run dry of work.6 Effective but not necessarily efficient. This  is needed because hearing lengths are difficult to predict. Moreover, some matters settle at court, as set out above. Some the afternoon before. For some matters, nobody turns up. The parties have moved on and not felt it important to inform the court.

As to providing the opportunity for taking instructions and negotiation that is, surely, a matter that the parties can be compelled to address, by telephone or video, on the previous afternoon. The courts here can borrow ideas from Single-Minute Exchange of Dies. This, in any event, seems a good idea. The parties would then be attending court ready to go. The waiting facilities would not be needed for their benefit. The court door settlements would have been dealt with.

The only people who need waiting accommodation are the participants in the next hearing. In most cases they can be accommodated, distanced and will have sufficient, even if sparse, washing facilities. These ideas are not foreign to the court system. It has been many years since a litigant or lawyer could just turn up at the court counter without first telephoning for an appointment, even on an urgent matter.

That probably involves some less ambitious listing of hearings. It may well have moved the constraint away from the judge to the queuing of parties into court. However, once the system is established, and recognised as the constraint, it is there to be improved. Worked on constantly. Thought about in the bath. Worried at on a daily basis.

Generate data. Analyse it. Act on it. Work. Use an improvement process. DMAIC is great but other improvement processes are available.

I’m sure all this thinking is going on. I can say no more.


  1. Image courtesy of Wikipedia and subject to Creative Commons license – for details see here
  2. Goldratt, E M & Cox, J (1984) The Goal: A Process of Ongoing Improvement, Gower
  3. Lepore, D & Cohen, O (1999) Deming and Goldratt: The Theory of Constraints and the System of Profound Knowledge, North River Press
  4. Kahneman, D (2011) Thinking, Fast and Slow, Allen Lane, p240
  5. What a good supermarket looks like“, Planet Lean, 4 April 2019, retrieved 24/5/20
  6. Rother, M & Shook, J (2003) Learning to See: Value-stream Mapping to Create Value and Eliminate Muda, Lean Enterprise Institute, p46



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