Critical path-Longhest path

Rachel,

You probably do have a longest path.  I am guessing that you constrained the finish milestone with a mandatory finish constraint and that your overall project has float.  That would place your finish milestone as the sole member of the longest path.  What you are saying with the mandatory finish constraint is that the contractor is not allowed to finish early as well as late.  That would make for an interesting contract.

To understand the longest path, you need to understand the calculations behind it.  Perhaps a paper that I presented way back in 2004 called, “Longest Path Value” might be of help.  You can find this at http://www.ronwinterconsulting.com/published.htm.  Good luck!

Ronald,

thanks for your advise. I removed the constraint and the longhest path appeared but as you said the overall project has float. So the critical path is not as I expected to be. In cases like that can we consider as critical activities also the activities with a float <3 to 4 days? I mean in construction projects is reasonable to make such assumption in order to be alerted?

One formal definition of the Critical Path is the path with the lowest total float.  That number does not need to be zero but may be more or less, depending on circumstances.  You can set a number other than zero on the Projects / Settings tab in the “Define Critical Activities” section.

I also think that you are using the wrong constraint for the end of your project.  Unless there is a penalty for early completion, then I would suggest constraining it to “Finish On or Before” a certain date.  Good luck!