As with other features in Estimating, planning is the key to building successful models. A model is only as useful as the components and values it provides. If a model lacks a critical piece of information, any estimate it produces will be inaccurate. Careful analysis will enable you to develop meaningful and complete models.

Before you start building models, you should:

• Develop a models coding scheme
• Consider the purpose of each model
• List the assemblies and items required for each model
• Decide how to enter input for each model