Outcomes of interest, statistical methods, baseline data, number of participants analyzed, and effects found (Consort items 6, 8, 12, 15, 16, 17, and 18) are presented in Table 2. Table 3 presents elements of study validity found to be important: sample size, recruitment, random allocation, blinding of assessor, participant flow (Consort items 7, 14, 9, 11, and 13).
Prior to recruitment, a random number drawn from a (0,1) uniform distribution (using the random number generator in SAS) was allocated to a participant number (which were consecutive integer values starting at 1).
Recruitment was random by sex and numbers of contact persons.
Prior to commencement of recruitment, a random allocation sequence will be generated using SPSS through consultation with an independent statistician not actively involved in the project.
For treatment recruitment, where random selection was not feasible (due primarily to small numbers of incoming patients), sequential new admits were screened for eligibility and all meeting the criteria were invited to participate in the survey.
The current study was unique in that it integrated elements of biomedical CVD research design, such as recruitment by random selection (not consistent with Māori cultural processes in which tribal leaders would select participants) within a kaupapa Māori framework.
The entry criteria for the CoolCap and TOBY trials also included abnormal amplitude integrated electroencephalogram. Infants were at least 36 weeks' gestation at recruitment, and random allocation was completed by 6 hours after birth.
This may reflect the methods used in UKCTOCS: recruitment by random invitation using participating local authorities' registers to select participants who are more representative of the general population than those who self-refer through advertisements (Menon et al, 2008, 2009).
The purpose of this short report is to examine potential non-response biases (e.g., in terms of number of attempted contacts) in self-reported data introduced during the recruitment to random digit dial surveys and how these may influence trend estimates, using the example of PA.
Raters independently categorised the articles as high, acceptable or poor quality, based on an evaluation of study design, participants (N, and type), demographics, recruitment method (random or other), exclusionary criteria, method of assessing perceptions (interview, questionnaire) and question quality (clarity, appropriate response options) (see online supplementary appendix 2).
From the remaining cohort of women in the Million Women Study with no HES record for vascular disease during the study time period (i.e. none of the above ICD-10 codes after recruitment), a random sample of about a thousand women was also selected.
