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The Critical Path

The Management Pocketbooks Pocket Correspondence Course

Pocketblog has gone back to basics. This is part of an extended management course.


We are working through a series of blogs, looking at some of the essential models that a project manager will need. We are covering:

 


One of the pieces of project jargon that causes most confusion is ‘Critical Path’ and ‘Critical Path Analysis’, the process of calculating the critical path. The concept is actually quite simple, providing you start at the beginning.

Tasks, Duration and Sequence

The first step in preparing a project plan is to identify all of the tasks you will need to complete. When you have done this, for each task, you must estimate how long it will take. The third key step is to figure out how the tasks connect up, logically, into a sequence. For most of them, one task will be followed by another, which will be followed by another. In project management jargon, this is a series of ’finish-to-start dependencies’. This sequence creates what is known as a ‘work stream’. The complications arise when some tasks can run in parallel to one-another, when some tasks can trigger the start of more than one task, and when some tasks can only start when more than one task has finished. There are more complications than this, but that’s enough and covers most small to medium sized projects! The best way to make sense of all of this is to draw yourself a flow chart; what is known as a ‘network diagram’. Network Diagram

Calculate the Critical Path

Once you have the logic of your network drawn out, you can add your estimates of the duration of each task. These will allow you to calculate how long each path through the network will take. The longest path is called the ‘Critical Path’. It is critical because any delay (or ‘slippage’) to a task on that path will cause a delay in the completion of your project. Critical Path on a Network Diagram There you have it – simple in concept. Of course, like much that is simple, in the real world it is seldom easy. Calculating (and optimising) the critical path for a large, complex project with very many interdependent tasks is a big computation. When the methodology was invented in the 1950s, it was a big job to undertake. Nowadays, all but the very the biggest projects can be planned, optimised and monitored with the help of software running on a standard personal computer. I will never forget having the chance to look through the network diagram of the project to build and launch the first NASA Space Shuttle. Hundreds of pages of large paper and small print. ‘But’ said the project manager who showed me it, ‘when they planned the Mercury and Gemini missions in the 1950s, every time an engineer or project manager wanted to change the logical sequence, the network (or a chunk of it) had to be re-drawn by hand.’ How would that affect our attitude to getting it right the first time?
Further Reading  From the Management Pocketbooks series:

  1. Project Management Pocketbook
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Karol Adamiecki: Management Harmony

We tend to think of leading management theorists as coming from the United States. This seems especially so of Scientific Management. But when the privilege of naming things for the world’s largest audience goes to those who write in English, history creates a bias. And because that audience largely reads only one language, that bias gets amplified.

One of many losers from the Anglo-centric nature of management and business thinking was Karol Adamiecki. He was a Polish engineer, turned economist and management thinker, who can claim to have invented the Gantt Chart before Henry Gantt, PERT before the US Navy, the Theory of Constraints before Eliyahu Goldratt, and much of Scientific Management before FW Taylor.

Karol Adamiecki 1866-1933
Karol Adamiecki 1866-1933

Short Biography

Karol Adamiecki was born in southern Poland, in 1866. He studied engineering at the Institute of Technology in St Petersburg, graduating in 1891. He then returned to his home town, where he took charge of a steel mill. He stayed for nearly 30 years, during which time, he formed his ideas about management.

In 1919, he left the mill, and became a lecturer at the Warsaw Polytechnic, becoming a professor in 1922. There, he further codified and published his ideas. In 1925, he founded the Institute of Scientific Management in Warsaw, becoming its Director and remaining until his death in 1933.

Adamiecki’s  Law of Harmony in Management

While running the steel rolling mill, Karol Adamiecki developed sophisticated thinking around management that was, from our perspective, ahead of its time. The three principal components were:

  1. Harmony of Choice
    Management should select and supply production tools that are mutually compatible. He went on to argue that this should be especially so in terms of their output production speed. This anticipated the Theory of Constraints, and the ideas of Eliyahu Goldratt by 75 years or more.
  2. Harmony of Doing
    Sequencing and scheduling of activities need to be fully co-ordinated to optimise production efficiency. Here, he not only developed a tool that looks very similar to the Gantt Chart, well before Gantt published. His approach also anticipated the US Navy’s Program Evaluation and Review Technique (PERT) and du Pont’s Critical Path Method (CPM) by over 50 years.
  3. Harmony of Spirit
    I imagine the Pharaohs’ overseers were constantly emphasising the importance of creating a good team. But this is another theme that feels very modern – perhaps even more so than the other two. Let’s not forget that Taylor’s view of Scientific Management was mechanistic and process-oriented. It took Mayo to bring humanism to the fore, and ideas of team working in management only started to dominate from the 1970s.

Adamiecki started to publish in 1898, several years before Taylor did so.

Harmony of Doing:
The Harmonograph or Harmonogram (or Harmonograf)

In 1896, Adamiecki solved the problem of sequencing and scheduling in production and published, in1903, his solution. He called it a Harmonograf. And it looks very much like what we now call a Gantt Chart. However, Henry Gantt did not publish until 1910. There is no evidence to suggest Gantt copied Adamiecki’s idea.

In constructing the Harmonograf, however, Adamiecki describes a process that is pretty similar to the PERT and CPM methods. He certainly is able to include critical path and float. These are two concepts Gantt did not consider at all.

As Adamiecki described his methods, he was able to optimise production schedules by sliding paper tabs and arranging paper strips. In a very real sense, he developed an analog scheduling computer.

Assessment

Without a doubt, Adamiecki’s thinking was of its time, but way ahead of its rediscovery. He possibly failed to realise just how valuable it was. But more likely, he simply suffered from an Anglophone bias in scholarship and manufacturing. Publishing in Polish simply did not get him recognition far beyond the borders of his home country. Even now, it is only in the Karol Adamiecki University of Economics in Katowice, that his name is celebrated.

And I have to ask, could this happen again? Yes. I think it can, will and probably is happening now. Last week, we met Vlatka Hlupic. Arguably, her work is known despite her Croatian origin, because she lives and works in London. With the US and the UK increasingly looking to close their borders for differing but related reasons, the next Karol Adamiecki’s work could well lay undiscovered for just as long as that of the first.

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