Size refers to the estimated total amount of time it could typically take to study and be assessed for a qualification. This could be anything from a matter of hours to a number of years of study and different learners could take a variation of time to study for the same qualification. Size is expressed in terms of Total Qualification Time (TQT). The part of that time typically being spent taught or supervised, rather than studying alone, is known as Guided Learning Hours.
Qualifications can sit at different levels, but require similar amounts of study as assessment time. Equally, qualifications at the same level can take different amounts of study and assessment time.