Fig. 1 shows a designer researching an existing product before designing a replacement. Explain the research the designer should carry out and how each part...

The research should investigate users, existing products and external constraints, then use the evidence to improve the replacement rather than relying on assumptions.

1. Observe and interview current users. Observation identifies what actually causes difficulty during use, while interviews reveal users’ reasons, needs and preferences. This gives evidence for changes that solve real problems. [2]
2. Disassemble the existing product and competitors’ products. This reveals materials, components, joining methods and assembly order, as well as where cost has been spent. The designer can then judge which construction choices to retain, improve or avoid. [2]
3. Review published standards and regulations. These identify requirements that the replacement product must meet, for example safety-related requirements. [1]
4. Gather anthropometric data for the intended users. Measurements such as hand size help set suitable product dimensions and operating forces in the specification. [1]

For the highest level, link several methods to specific design decisions and make a judgement: combining direct user evidence with product analysis and published requirements gives a more reliable basis for a replacement than any single method alone.