An IBM colleague has been keeping track of time usage by his developers (off shore) over the last week. He found it surprising that only 50% of the time was actually used for development. The rest of the time was take up by communications, knowledge transfer (basically ramp up of new developers), maintainance issues (dealing with customers on the phone doing second level support), etc.
Having read Peopleware: Productive Projects and Teams, by Tom DeMarco & Timothy Lister, (December 1999, ISBN 0932633439) I wasn’t that surprised. It explains why I’ve always found that doubling an estimate magically makes it accurate.
My IBM colleague is going to continue to monitor for a few weeks, so if the results change, I will let you know!