[trop]

An anecdote from someone in IT at a major university: The registrar has two employees whose sole job is to write SQL queries. These are to answer basic questions such as, "How many undergraduates are currently enrolled." And it turns out that this is a nearly impossible question to which to give a definitive answer.

[MaxBarraclough]

Shouldn't the finance folks know that kind of thing pretty definitively?

[bluGill]

What does it mean to be enrolled? What if someone takes a semester off? What if they are part time? What if they are on a foreign exchange program this year? What if ...

The above are the type of questions that can result in different definitions of enrolled.