The study ID has three components:
Study IDs are stored as character variables but a decimal point is included between the site code and randomisation to allow the ID to be more easily converted to a numberical variable and manuipulated. The randomisation number is assigned after randomisation and is sequential at each site, allowing sites to monitor their recruitment. The study number is essential to ensure that records and sample between studies remain separate.
The following site codes have been used in previous Australasian multicentre trials and are recommended for continuity:
To deal with unit of analysis issues, there are two common solutions: