User-centered design of power tools: a generic process for evaluation of usability aspects [Die Nutzerzentrierte Produktentwicklung von Power-Tools: Ein generischer Prozess zur Untersuchung von Usability-Aspekten]

User-centered design focuses on the individual needs of the product users. The aim is to adjust the design of the product according to the requirements of the user and application. Existing methods for evaluation of the perceived usability are often limited to one specific aspect, and it requires a high effort to transfer the respective method to other aspects. A generic process for the evaluation of the perceived usability is missing. This paper presents the generic Usability Study Evaluation Process (USE-Process) that helps product designers to identify and evaluate usability aspects relevant to the suitability of the usage of a product. The process is divided into three sections:

1. A structured field study to identify the relevant usability aspects;

2. A generic study design for the subjective evaluation of usability aspects under objective and reproducible conditions;

3. The use of measurement tools that help to quantify the results of the subjective evaluation.

The generic applicability of the process is shown by the example of the evaluation of cordless screwdrivers; several usability aspects were identified, clustered, and evaluated by using subjective evaluation methods and measurement techniques.