Sir: Sainsbury’s recently announced it will overhaul its own-brand Basics range by adding larger blocks of colour and new product straplines. In our experience, marketers are more likely to be successful in redesigning a brand’s packaging by adhering to a few key principles.

Firstly, start at the shelf: be guided by an understanding of how people shop in a given category, including their incoming mindset and the visual cues they use to sort brands and products.

Secondly, confirm visual equities. Any redesign efforts should be rooted in an awareness of the two to three key design elements that your most loyal consumers use to recognise, identify and positively associate with your brand - in this case within and across categories. Thirdly a redesign should also be informed by a thorough understanding of the strengths and limitations of existing packaging.

And finally, effective packaging assessment is primarily a matter of simulating introduction rather than comparing old versus new packaging - and of documenting what shoppers do when presented with the new design, rather than relying solely on what they say about it.

Grant Montague, vice president - Europe, Perception Research Services