3.1 Introduction

This chapter presents a framework for cost-justifying usability engineering efforts on software development projects by describing how to calculate the costs and estimate the benefits of each of the Usability Engineering Lifecycle tasks that can potentially be applied (Mayhew, 1999). We present a general framework that is relevant to developing software for any application from commodity trading to a Web commerce site.

A usability engineering cost-benefit analysis is conducted in the software development process for two major reasons:

1. To demonstrate that usability engineering is a viable and significant cost saving approach

2. To plan the usability engineering program for a particular development project

General cost-benefit analyses of hypothetical usability engineering efforts can be prepared as a strategy to win general support for trying out usability engineering tasks and techniques in a software development organization. When an organization has no experience with usability engineering, cost-benefit analyses may be an effective way to free up resources for usability improvement efforts.

In organizations that are more mature with respect to usability engineering, cost-benefit analyses can be used to plan an optimal usability engineering program for a particular software development project. To help settle on a final usability engineering plan for a specific development project, costs are calculated for the most aggressive program that can be implemented, including the most reliable and thorough techniques for all Lifecycle tasks (see later discussion).