This leaves us with a pedagogical conundrum. Which method of calculating the sales volume variance should we teach? In turn, this is part of a wider question as to what we should teach in the business school. Should we teach from a normative perspective, telling students what we think is the right way to do things, without the benefit of our perspectives being validated by practice? Alternatively should we teach students what is actually in use by practitioners, and ignore the existence of better methods? Or should we try to teach both known practice and how to improve practice by adopting better models? If we choose this third approach, where, in this world of expanding knowledge, will professors and students ever get the time to do justice to it all?