Respondents were representative of the trial participants.
The demographic characteristics of patients and GPs; and distress levels of the patients, were representative of the trial participants and the interpretation of the data was conducted with rigor by two researchers.
To assess whether the 74 patients in this study were representative of the trial population, the patient characteristics were compared with the other 317 patients randomised by EORTC and NCIC centres, which contributed to the sample collection, and no significant differences were observed.
JTS was the National Institutes of Mental Health representative on the trial, member of the executive committee, and helped to draft the manuscript.
A limitation of this research is that the sample inevitably comprises only those people willing to be interviewed and is, therefore, likely to be non-representative of the trial population.
Representatives of the trial sponsor and funder should be invited to all TSC meetings.
Patients were purposively selected so that the sample comprised equal numbers from across the trial's three treatment arms; was broadly representative of the wider trial population in terms of age, sex, and glycemic control (Table 1); and included trial participants with high and low final A1C results (range, 5.3 9.9%).
This is consistent with the trial population as a whole, suggesting the sample is representative of the wider trial, although participants in the present study tended to be older.
Although this had the advantage of enabling us to generate numbers from qualitative data for a relatively large and representative proportion of the trial population (7.7%) across multiple sites, it also brought with it a number of technical problems.
The study is unique in having integrated these into the trial in order to improve accuracy rather than using them for parallel or retrospective evaluations, and in the way that the qualitative data were collected from a substantial representative sample of the trial population.
It may also increase generalizability by ensuring that patients who require treatment more often in usual clinical practice make up a representative proportion of the trial observations.
