Critical Chain Project Management: (A Paradigm Shift in Project Management)
Among various resources required to complete any project,time is one of the most critical resources, but is not the only one. And it is because of this reason that time as a resource is given the utmost importance in any project, so much so, that it is studied and managed separately from all other (tangible) resources, and not only that, even the termtime has been kept out of the definition of the termresource especially when these terms are referred in the discipline of Project Management.
Keeping in mind the peculiar nature of time vis-vis all other (tangible) resources, this is a good practice to keep the termtime separate from the termresource, and the same practice shall be followed in this paper as well, but the practice of managingtime in isolation withresource is a matter which we need to rethink about and is one of the issues which this paper intends to address.
There has been in practice enough number of techniques to manage both thetime as well as theresources in the discipline of project management. Barring few drawbacks, all these techniques have been very useful as long as they are to be used in isolation to each other, i.e. either to manage thetime or theresources.
However, the need of the present competitive world of project management, which hitherto (esp. before the introduction ofCritical Chain Project Management) had been ignored, is the integration of the two. Critical Chain Project Management not only takes into account both these critical inputs of a project i.e. the time and the resource, but also has many other advantages over its counterpart traditional project management practices.
What is Critical Chain Project Management (CCPM)?
Although, the significance of the well-known techniques, like PERT/CPM (Performance Evaluation Review Technique/ Critical Path Method), cannot be totally undermined, but the kind of revolutionary change, Mr. Eliyahu Goldratt, the inventor of theTheory of Constraints, has brought about by propounding a yet another milestone concept calledCritical Chain, calls for further research in this field so that CCPM gets the deserved recognition, and the main objective of this paper is also to make one such attempt.
Although, the complete concept will become clearer only gradually while going through this paper, but before that, let us first briefly understand what the CCPM is all about.
The key features of Critical Chain Project Management are
1. Task times are reduced from conservative to realistic task estimates
2. Resource Conflicts are removed
3. Critical Chain is identified as the longest path considering both task logic and the resource contention.
4. Project Buffer is placed at the end of the critical chain
5. Resource Buffers are also placed to ensure the availability of resources at right time in right quantity.
6. Feeding buffers are placed at the joints where non-critical chains feed into the critical chain.
7. Activities are started onAs Late as Possible philosophy after taking into account; the task logic, resource contention, and project completion time etc.
8. Buffers are used as measures to control project performance.
All the above mentioned features differentiate it (CCPM) from other traditional project management techniques.
Advantages of CCPM over its counterpart traditional project management techniques
Time vs. Cost: Moving fromZero-sum game toWin-win situation
In all traditional techniques, it is assumed that the two critical inputs of any project namely theTime and theCost can strike a balance only at the expense of each other, exactly like it happens in a zero-sum game. That is, if someone is to make a project time-efficient, he/she has no option but to bear the additional cost (a phenomenon known ascrashing) and vice versa.
However, the technique of CCPM is against this notion and has given us a better solution whereby we can not only become time-efficient by adopting aggressive scheduling technique, but alsocost-efficient by making optimum utilization of resources as well as by reduced project completion time which results into the reduction of indirect costs.
Change in Attitude: From being Pessimistic to being Optimistic
Generally, in order to deal with the uncertainty involved in the work, people tend to addsafety margins while scheduling tasks because they know that they will be held accountable for delivering against their estimates, and which is why they make very pessimistic estimates generally at 90 to 95 % confidence level.
However, in CCPM, the task duration estimates are brought down to a very optimistic level usually till 50% confidence level, which is nothing but theaverage expected task duration. The idea is to deal with the Parkinsons Law, according to which,Work expands to fill (and often exceed) the time allowed. These aggressive estimates not only make the people work hard to meet the tight deadlines, but also change their attitude by making them more optimistic towards time estimation.
Resource allocation: From multitasking approach to focused single task approach.
Why resources make pessimistic estimates is also because they know that, at times, they have to work simultaneously on more than one task, and in the process, they tend to devote maximum of their time on the tasks which are more important and urgent at a given point of time.
In such cases, we have one resource struggling among various competing priorities, which results into the sub-standard performance and therefore all those tasks which are scheduled simultaneous & competing for the same resource suffer because of unfocussed attention & at times, complete unavailability of the resource.
For example, if one resource performs three tasks simultaneously, he finishes all the three tasks at the same time either at the end of the total time allotted to him for finishing three tasks, or may be even later than that because of unfocussed and distributed attention. However, if the same resource focuses on one task at a time, he/she can prioritize and finish the task which is most important among the three in around one third of the time and therefore can pave the way for the tasks which are having this particular task as their predecessor.
In view of above, in CCPM the activities are scheduled in such a way that one particular resource has only one task at his hand at a given point of time, so that all of his/her energy is focused towards one task only.
However, depending upon the nature of the project and the tasks therein and the capability of the resource, sometimes multitasking can be preferred oversingle task approach if any individual task asks for lesser attention of the resource and provides more idle or spare time to the resource which can be devoted to other similar tasks, which also require the moderate attention and efforts of the resource.
Scheduling: Both aggressive as well as realistic
The need of the hour is that we should have a project management technique which can address not only the need for speed but also the need for reliability and what is more, both at the same time.
CCPM, fortunately, has an answer to this, as with the help of this technique we can not only increase the speed by reducing the task estimate durations but also increase the reliability by making the estimates realistic with the help ofproject buffers as well asfeeding buffers.
Corrective actions at initial stage
When we have pessimistic schedules, the promised date to finish any task looks like a long way off due to the safety included in the estimate itself, and we can find the reason to finish other important works first and therefore we tend to start the task as late as possible.
The unexpected problems, which can only be identified when we actually start the task, ask for some corrective actions and since the time allotted for which has already been consumed simply by starting the task late, therefore any corrective action here will consume additional (unplanned for) time resulting into the delaying of task & in turn the project.
However, in CCPM, since all the tasks are aggressively scheduled, leaving no room for deferment, and therefore, the task actually gets started when it is scheduled to start and any problem arising during the progress of the task can be corrected at the initial stage itself and the time consumed therein will consume the safety buffers and will not delay the project.