“Biomimicry in Action” : designing with nature’s technology

Based on the International Standards Organisation's categories of "effectiveness, efficiency and satisfaction," the author determines ways in which usability can be quantified. 'Effectiveness' is the capacity for a product to generate (or enable) output; 'Efficiency' is measured as the level of effort invested in completing an action or task (for example, the author categorizes usability errors as distinguished between a 'slip' and a 'mistake' in user performance and experience. For him, a slip is when a user accidentally performs the wrong action which is readily corrected by the user, whereas a mistake is when a user thinks he is doing the right thing (intuitive action), but is unable to perform his task.

Before you begin testing it is important to set your primary evaluation goals and concerns. Once those have been defined, it will be possible to plan a usability test accordingly. Dumas & Redish raise the following processes: making choices among goals and concerns; moving from general concerns to specific ones; and understanding sources of goals and concerns.