TABLE OF CONTENTS To cost-justify a usability engineering plan, you simply adapt a very generic and widely used cost-benefit analysis technique. Having laid out a detailed usability project plan based on Lifecycle tasks (see previous sections, and Mayhew, 1999), it is a fairly straightforward matter to calculate the costs of that plan. Then you need to calculate the benefits. This is a little trickier, and it is where the adaptation of the generic analysis comes into play (see later discussion). Then you simply compare costs to benefits to find out if and to what extent the benefits outweigh the costs. If they do to a satisfactory extent, then you have cost-justified the planned effort.
More specifically, first a usability engineering plan is laid out. The plan specifies particular techniques to employ for each Usability Engineering Lifecycle task, breaks the techniques down into steps, and specifies the personnel hours and equipment costs for each step. The cost of each task is then calculated by multiplying the total number of hours for each type of personnel by their effective hourly wage (fully loaded, i.e., including salary, benefits, office space, equipment, utilities, and other facilities), and adding up personnel costs across types. (Sometimes it is hard to get data on fully loaded wages for an organization. In this case, I (Mayhew) use a rule of thumb I have heard informally and simply double the before-tax annual salary, then divide by the typical number of hours a full-time worker is paid for in a...
