Page tree

Versions Compared


  • This line was added.
  • This line was removed.
  • Formatting was changed.

ID Schema


Schema for Multicentre Trials

We use a study ID consisting of 3 components in the format XXXXXX.XXXX:

  • 2 digit study number
  • 4 digit site code
  • 4 digit randomisation number


Study IDs are stored as character variables but a decimal point is included Study IDs are stored as character values to ensure that zero place holders are not dropped. The randomisation number is assigned sequentially at each site after randomisation. A decimal point is placed 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:

Randomisation in multiple pregnancy

To deal with unit of analysis issues, there are two common solutions:


number. This allows sites to monitor their own recruitment and ensures the ID can be easily converted to a numerical value if manipulations are required. The study number ensures that samples and data can be identified across studies. Site codes are based on those used in previous Australasian multicentre trials.

For perinatal studies,  we recommend the following numbering:

  • Mother first pregnancy in study XXXXXX.0001 to XXXXXX.2999
  • Mother second pregnancy in study XXXXXXX.9001 to XXXXXX.9999
  • Singleton fetus/neonate XXXXXX.3001 to XXXXXX.5999
  • First twin or triplet XXXXXX.6001 to XXXXXX.6999
  • Second twin or triplet XXXXXX.7001 to XXXXXX.7999
  • Third triplet XXXXXX.8001 to XXXXXX.8999

Click here for the complete list of LifePath study and site codes.