Customer responsibility for ensuring usability: Requirements on the user interface development process

Abstract

An organization developing an interactive system will often find usability a compelling, but elusive, goal. The goal of ensuring usability becomes even more difficult to attain when the system is contracted to an outside developer, and control of both process and product becomes remote. Without a clear statement of requirements for the user interface of the system, this control may be lost from the beginning. Further, the cost of interactive system usage is especially significant in the case of contracted-out development, because the customer—the organization that lets a contract for interactive system development—bears the costs of training and poor user productivity. In spite of the good publicity that usability has received lately, most customers still do not state requirements for the user interface of an interactive system. Although it has been shown that the process by which a user interface is developed has an overwhelmingly large effect on usability of the product, almost never are requirements for the interface development process included in the overall system requirements. How, then, can a customer hope to ensure usability in an interactive system that the customer is contracting out for development? We propose a solution: The customer establishes requirements for the user interface development process, even as early as a Request for Proposal (RFP). To successfully write and enforce such requirements, the customer (or a knowledgeable representative of the customer) must be well informed about human-computer interaction, usability, and existing user interface development techniques. As a case study, we describe how one customer organization, the Bureau of Land Management, produced user interface development process requirements and included them in an RFP. We also discuss how a customer can use product requirements in an RFP to describe the desired general interface style without constraining the developer to a specific design.