CRITICAL PATH

   

CRITICAL PATH

Critical path is important for a number of reasons.

  • It tells you the shortest possible time in which the project will complete.

  • It identifies those jobs which, if they are delayed, will result in a delay or slip in the project as a whole.

  • It identifies those tasks which must be shortened if the project is to be shortened .

  • If a slip occurs on your project, the critical path identifies the jobs which must be worked on if the project is to be brought back on schedule.

  • The critical path is the reason why adding more people to a project may not necessarily make the kind of difference we would expect. To illustrate this let's see what happens if we add some people to our project above.

Nearly 70 percent of the effort on this project is taken up with two tasks: write document and revise document. If we were to add a person or even two people to these tasks our natural reaction would be to expect a substantial improvement on the schedule.

In practice, nothing could be further from the truth. Adding one person (i.e. increasing the team by 50 percent) reduces the schedule to

5 + 0.5 + 5 + 1.5 + 0.5 + 5 = 17.5, a saving of 15 percent on the original;

while adding another person and increasing the team by 100 percent reduces the schedule to

4 + 0.5 + 5 + 1 + 0.5 + 5 = 16.0, a saving of only 21 percent on the original.

And note that adding more people assumes that they can just slot in with no prior knowledge of the particular task, and be as productive as the people who were already there. Such an assumption is rarely the case in IT.

Indeed, there is an argument that says that in certain circumstances adding people to a project will not actually shorten the schedule at all. This argument is succinctly stated in Brook's Law (Brooks, 1975).

Adding people to a late project makes it later.

   


How To Run Successful Projects III. The Silver Bullet
How to Run Successful Projects III: The Silver Bullet (3rd Edition)
ISBN: 0201748061
EAN: 2147483647
Year: 2001
Pages: 176

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net