Where possible these variables were considered as having a linear continuous-scale relationship with WC change rather than using categorisations that may be arbitrary.
We also evaluated alternative categorisations for BMI and MHT using categorisations used in prior studies (BMI: ⩽24, >24 kg m−2; MHT: never, ever) (Vatten and Kvinnsland, 1990; Ursin et al, 2005).
As the results of both analyses were similar we used categorisation.
The first (i) involved coding on the basis of previously used categorisation systems that have described components of care.
(Interview 28) One of the most commonly used categorisations stated by the study participants – often the sole or fundamental one – was the level of satisfaction with medical care.
Comparisons of claims between ophthalmic subspecialties in the literature are much less complete than the present study, and have used categorisations more of interest to insurers than to doctors [ 7].
Therefore, using this categorisation enables us to work with a measure of employment status that implicitly takes into account the characteristics of the job as regards the length of the working day.
Exposure to solar radiation is usually estimated using exposure categorisation (recreational or occupational) or job categorisation (indoor or outdoor).
Mapping of standards to W3C technologies was done using the categorisation of standards by W3C10.
