Variable Name Schema

  1. CRF abbreviation: 2-3 characters (case insensitive, no numbers)
  2. Question number: 2 digits (use 0 place holder for 1-9)      
  3. Underscore _      
  4. Sub-question number (2 digits or characters, use 0 placeholder)      
  5. Underscore _      
  6. Short descriptor <=10 characters, can use camel case      
  7. Underscore _      
  8. Optional descriptor modifiers 
    1. Subject identifier (- important if mother, child, father connected by same study ID)      
      1. Mo = mother     
      2. Fo = father     
      3. Ch = child
    2. Variable type       
      1. bn = binary (0,1) 
      2. yn = yes no
      3. sp= specify (free text) 
  9. Underscore _ 
  10. Event identifier      
    1. nA = Antenatal e.g. A, 20A, 36A : antenatal, 20 weeks antenatal, 36 weeks antenatal      
    2. B = Birth      
    3. nW= where n is a digit and W is weeks      
    4. nM = where n is a digit and M is Months      
    5. nY = where n  is a number  and Y is year 

Variables should be limited to 28 characters so that a suffix or prefix can still be added. Do not include the unit of measure in the variable name (will be specified in study procedures).