A further 281 comments were from those who self-categorised as 'other' and wrote their profession in a free text box.
Self-perceptions categorised as positive or negative have been found to have a differential impact on functional health at 18-year follow-up [ 1] and even more importantly, on rates of mortality at 23-year follow-up [ 2].
Single self experiments have been categorised as self indulgence or abuse, and trivial interventions masquerading as research studies as a source of amusement.
In the second experiment (incidental self processing), subjects categorised words according to whether they described physical versus psychological attributes, while unaware that the words had been arranged in blocks according to self descriptiveness.
Ethnic group was self reported and categorised as Malays, Chinese, Indians and Others.
**Race or ethnic group was self reported and categorised according to standard UK census categories.
The exposure of interest, commuting mode, was self reported and categorised as three categories: private transport, public transport, and active transport.
To avoid self interpretation, we categorised the deviations by rigorously following the author's descriptions of modified intention to treat and independently of other descriptions relating to exclusions of participants.
Sex and marital status were self-identified and categorised into male, female, married, unmarried, respectively.
Mother's skin colour was self-reported and categorised as white or black/mixed.
Pain was self-reported and categorised as either 'no pain' or 'pain' over the last 4 weeks.
