Critical Path Methodology has formed the heart of most of today’s modern project scheduling systems.  Is it time for something new?

 Many of us remember what it was like; Aerospace and Defense were spending money on a scale never before seen in peacetime.  Construction and infrastructure projects were beyond comprehension in their scope and vision.  It started in the 50’s and lasted until the end of the 80’s.  It was the era of the mega project.  It started with a post-war world and saw us through the cold war and the placing of a man on the moon and the birth of the modern computer.  It saw power projects that harnessed rivers and atoms and for project management as a discipline, it was a time of coming of age.

Project management has been around of course as long as there have been projects.  The Pharoses used some kind of project management on the creation of the pyramids and I’m sure every great project has seen some kind of management since the dawn of time.  But never before in the history of the world have so many great projects happened simultaneously.  No, history will record the birth of the discipline of project management in the middle of the last century – circa 1950.

The birth of CPM
For those of us who were able to work on some of those mega projects, you can remember how they were organized;  First of all, there were lots of activities.  I mean lots.  There were effectively unlimited resources.  Those resources were expected to work across multiple years to accomplish their task.  Time was the only constraint and the pressure to finish early, finish on time, not to be late drove everything.  If you were in aerospace it was the “space race”.  If you were in Defense, it was the “arms race”.  If you were building infrastructure to accommodate the new world it was about finishing fast enough to just keep up with demand. 

It was into this world that Critical Path Methodology was born.  It was miraculous.  For the first time, we could look at a project and know just what tasks we had to focus on in order to avoid delaying the project.  We learned about forward and backward passes and early vs. late dates.  There were variants and innovative displays.  Gantt had his bar chart and the US navy came up with PERT.  It was all designed to focus on one thing – “Don’t be late.”

Early computerized CPM systems
The application of computers to this calculation methodology was a natural.  With all the calculations to do, it seems obvious.  In fact, as computers have evolved, one of the first business applications to appear in each new iteration has been a project management system.  Computers were tailor made to handle the arduous yet clearly defined calculations, enabling project teams to adjust their forecasts as fast as events occurred.

Yet these systems were created in the world of the time.  Project Management Systems they were called and, indeed, they were in the project management category but what we all knew we meant was that these were CPM scheduling systems.

Those first systems didn’t look much like the graphical, easy-to-use systems of today.  The earliest systems on mainframes and mini-computers were originally loaded with punch cards.  Even once “on-line” systems became available they looked more like an airlines reservation system than today’s point-and-click.  The fundamental algorithm though of those original scheduling systems is essentially unchanged over the years.  Even as systems became available on PCs they showed the bias of the times.  Early project scheduling systems didn’t do resource leveling.  It was a later invention.  In fact, with some systems, the resource calculator was sold separately as an add-on.  Resource-limited scheduling?  It was an afterthought.  Remember, resources on a mega project were essentially considered unlimited.  There was no thought of scheduling all the way down to the individual level.  Resources were considered at best as disciplines or categories.  Graphical reports were considered a luxury that not everyone wanted or needed (Can anyone say “Primavision”?).  These days we talk about resource calendars and split activities but there was nothing like that in the thinking of the time.  I remember the first system I worked with having 8 calendars – Whatever would I do with all those calendars? I wondered.  Baseline changes were also something not originally conceived.  No one much cared how the mega project had originally been planned.  All that counted was when it would be finished.

The PC-based software that got its start in the early 80’s is still very much a part of today’s market.  And, while those products have advanced with the times, for those of us who have seen those products since their first versions, we can see the traces of their original design.

Yes, it was a different time but the software we see today had its start there and for the most part, the changes we’ve seen over years in that software have been an evolving theme rather than a re-thinking for the times. 

Welcome to a new world
The world that project managers face today is a far cry from that of the 50’s through 90’s.  It is a function of today’s economy.  Today’s MTV generation lives in a world where 10 year long projects are remarkable exceptions.  Where an individual is more likely to be working on multiple projects at one time – even multiple projects in a single day.  It is the world where time to market, shorter run times, design/build, RAD (Rapid Application Development) rule – and it is skewing everything we know about project management.


While the world was changing for project managers, the world of computers was changing too.  We tend to think a lot about the impact of Windows on the current landscape and of course with that thought about Microsoft must come a thought about MS Project but when you look at the core, the most significant changes in project management products have been interface-driven.  After all that was Windows’ claim to fame.  It made the PC interface so easy that a whole new category of user was able to adopt it and become proficient with must less training.  Changes in project management software have been focused on these areas.  On-line tutorials, user-friendliness, flashy, sexy, fun to use software make for more sales.  Yet, the basic concept of the vast majority of these products continues to be based around the old CPM model.

Microsoft tried to break out of the model a couple of years ago.  There’s a famous (infamous?) white paper written by someone at Microsoft from a few years ago describing how MS Project version 3 “de-emphasized” the CPM model.  It may be true, but if you do a calculation of schedule in MS Project, guess what algorithm is used.  No – at its heart MS Project is still a CPM product.

Sure, there have been plenty of additions and enhancements in all of the project management products popular today.  Some of them are remarkable.  Projects can now be huge and many high-end tools do multi-project scheduling.  Forget about 8 calendars and a single baseline – “unlimited” is the latest limit described by almost all PM software vendors on such functions.  There are hierarchical resources and integrated costing functions and risk analysis and so on and so on.  It’s remarkable but at its heart, most of these systems are still built around that original CPM algorithm. 

The CPM algorithm requires a few key elements in order to automatically calculate a schedule: It requires a list of tasks.  For each task, a duration or a method of calculating the duration must be given.  If there is a logical sequence to the tasks, this must also be defined and, given this information, a CPM calculation can tell you the earliest feasible date each task can start (and finish) and the latest date it can start (and finish) without delaying the project as a whole.  Resources may be defined along the way but basically the resource calculation is laid on top of the CPM dates and scheduled from there.

It sounds fine but remember the algorithm was designed in a period where the only driving criteria was “don’t be late”.

“And now, for something completely different”
Imagine a world where the driving criteria for successfully completing a project is the availability of highly skilled individuals.  A world where even the technology a project is based on will change multiple times over the life of the project.  (Sound familiar?)

I question whether the Critical Path Methodology algorithm is a useful method of analysis for many of today’s projects (Wait.  If you’re one of those Critical Chain advocates – please don’t be writing me explaining how different it is – I don’t believe that’s the answer either.)

In a world where skilled individual resources move from project to project over a period of hours – perhaps we need a whole new way of thinking about project management software.  It would have to be a completely new paradigm.  Something starting not with a list of tasks perhaps but with the capabilities of the resources and technology available to us.  Perhaps the projects and tasks one commits to and the schedule that becomes possible should be driven around available technology capacity and skills rather than the other way around.

There is a great focus at the moment on the Internet and the Web and how marvelous it is to be able to work across a world-wide network.  The focus is all too much on the interface for my tastes.  It makes for sexy press and I’m sure I’ll end up being a user or proponent of some of these systems.  I don’t doubt that there is merit in many of them; but it is a variant on a theme.  Being able to look at the same old paradigm in a web-browser is not a shift in thinking no matter how many new people will play with it because it is simpler to use. 

There is room in the project management software market I think; room for some innovation; room for something completely different.

There are a couple of firms, some new and some old who are touching on some of these new areas.  Some of these solutions are innovative but many were not ready for prime time.  I’ll be looking for developments from these firms throughout the year to see if they can get over the initial teething stages and get something into the market that addresses the new world we’re working in. One thing for sure, when there is a need in the marketplace, someone will find a way to fill it.  When I find some answers, I’ll let you know.