You NEED 3 things for your software estimates to be successful ,but 4 things if you want it to be repeatable, defendable, easy to use, and quick to make changes to…
1.You need qualified and experienced people to generate the estimates. They have to know how to estimate and they have to understand what the problem is that the project is going to solve…..at least well enough to estimate it. This can be one person or many depending on the difficulty of the business area. The harder it is, the better having more brains look at the problem. But not to the point where it can slow you down. A team of 2 to 5 people can be faster and more efficient that a team of 8 to 12 and it’s easier to reach consensus.
2. You need your own data as a reference point in the estimate. As a comparison or an analogy. Your own data makes selling and explaining the estimate easier. It provides context for it that can enable management to give a quicker and more reasonable answer.
3. The estimate must be used as part of the decision-making process. If it’s not used its wasted time and effort. When things get tight the estimation will go away.
4. Automated project estimating software tools to speed up the cost estimation solution process and to enable some more what if analysis can be indispensable,