Possible Duplicate:Why are software schedules so hard to define? I often need to explain to senior management why software estimation is so hard, and why our preliminary estimates are often so far out. I suspect some want to know why it is not mathematically precise engineering, like building a bridge.You can help me by listing a few dot points relevant to this subject. Many thanks!
Why is software schedule estimation so hard?
scheduling;software schedules
Software estimation isn't actually more difficult than estimating other types of work. It just seems so because the CONDITIONS under which it's estimated are more difficult. Say a software company was tasked with something similar to what a car company is tasked with. Build the same thing over and over again, which has existed for decades, and with only minor variations. Furthermore, you will work from a complete and detailed spec from the beginning of the project and it will be frozen once development begins. Under those circumstances software estimation would be cake.