Variable Naming Conventions

Variable 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).