1. A method for scenario-based design and development of a web-based user interface for effort estimation, the method comprising: receiving an indication of one or more accessibility guidelines; providing user-selectable scenarios for said web-based user interface based on requirements; exhibiting a work flow on a pre-populated work flow screen based on selected scenarios for said web-based user interface; providing a plurality of user-selectable web components; receiving an addition to the work flow of the pre-populated work flow screen; modifying the work flow based on the user-selectable web components; storing the work flow in a repository for proposing the pre-populated work flow screen with the addition to the work flow for new users; via an estimation process, calculating estimated effort by an effort estimation processor based on said modified work flow of the selected user-selectable scenarios, the addition to the work flow, and the accessibility guidelines; generating reports for each stage of development cycle; for a next user, displaying the pre-populated work flow screen with the addition to the work flow; and repeating the estimation process for the next user using the pre-populated work flow screen with the addition to the work flow.