A series of contextual interviews were conducted in public spaces of Helsinki, Milan and New York collecting 419 responses in total.
The results show a strong tendency by gender, with females using bags and males using trouser pockets to place their mobile phones.
Comments from participants suggested users did not place the phone wherever available, but rather considered many aspects, such as the convenience, tolerance to multiple postures, risk of theft, comfort, or impact to their appearance. The authors learnt that bag users miss incoming alerts more often than with other carrying methods.
Based on the outcome of the study, the authors discuss the challenges in designing mobile devices, in particular mobile phones, and suggest that phones need to be more noticeable as a notification device.
Download study (pdf, 343 kb, 8 pages)
(via Carolyn Wei, who also provides some additional notes on the study)