many things effect the ENTER of a course.
For instance:
*the name of the university.. I know a lot of people that have gone to Melbourne University because it has become well known and is rather prestigious.. for instance the enter for an arts degree might be higher then umm.. swinburne.. but that does not necessarily mean that it is better.. it is label.. it is like RipCurl ya know.. they charge $90 just for a t-shirt because it says RipCurl.
*the popularity - people tend to choose to do degrees at particular universities for their location. Eg. compare the enter for a course at a campus in Gippsland to one in Melbourne. The Melbourne ENTER will be higher not because it is necessarily better but because it is more popular because more people live there.. eg. more competition.
*the Government - I used to think that because the ENTER was really low (around 50) to study a degree in Mathematics at RMIT University that the course was in fact really crap. After some research I came to the conclusion that I was in fact wrong. RMIT is a pretty good uni btw. For one not many people are interesteded in mathematics and also the Government pressed that we need more mathematians so the score got lowered.
Choosing the right university takes some research and thought. I think some year 12 students are not aware of this... usually being stressed and pressed to just put any thing down.. so they just go by the ENTER... which is not the way to go. You need to go to open days, talk to previous students, compare the rate of employment, where they are being employed (they could fool you by saying people are getting employed after the degree but didn't care to mention they are working at Chop Soy factory that looks like a Prison), location, majors/minors, specialisation (RMIT is welll known being good in computers/engineering wheras Monash is for law), etc. The ENTER can give you an indication but by no means is it the decider.