13. A method for designing a customized user interface, comprising: categorizing a user population into at least two groups, describing the categorized groups, and modeling the described groups using qualitative and quantitative models, the categorizing, describing and modeling being based upon Categorize-Describe-Model (CDM) methodology; applying the models to interface design by analyzing screen flow including a prototypical screen flow; and creating the quantitative models based upon the screen flow analysis.
20. The method of claim 13 , further comprising iteratively testing the design.