To Angry Aussy: I had seen so many times angry and frustrated schedulers, because they have not been listening by the upper levels to make corrections when they can see the problems clearly. This doesn't mean that the main schedule is wrong. It is up to you how to use this tool, the worst part is keep tracking and up-dating the schedule because it is a hard work keep incorporating the changes and the progress. Most important, all the Key Players in the project need to be part of it, it is not one person's effort and it is not to blame each others. It is the oposite, to forecast and resolve issues that every project has.
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pmkb 
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