The Value Type of a Data-Field describes the type of variable corresponding to it. There are 9 categories:

• Integer - whole numbers, for example the age of a participant on a particular date;
• Categorical (single) - a single answer selected from a coded list or tree of mutually exclusive options, for example a yes/no choice;
• Categorical (multiple) - sets of answers selected from a coded list or tree of options, for instance concurrent medications;
• Continuous - floating-point numbers, for example the height of a participant;
• Text - data composed of alphanumeric characters, for example the first line of an address;
• Date - a calendar date, for example 14th October 2010;
• Time - a time, for example 13:38:05 on 14th October 2010;
• Compound - a set of values required as a whole to describe some compound property, for example an ECG trace;
• Binary object - a complex dataset (blob), for example an image;
• Records - a summary showing the volume of records data available via the secure portal.