Reflection on the types of students
I decided just under a year ago to open up my website to the public and release what I do to others outside my classroom. As a part of entering myself into the public I have been uploading videos to YouTube I took this screenshot of my analytics.
Taking into account that only about 10% of the IB Chemistry cohort will obtain a 7, it looks kind of similar to that, in that the 90% have decided to study just before the exam (the May spike) like the story of the rabbit and the turtle. The turtle has been working away hard at the videos all year and in the story wins the race. The rabbit makes a last minute dash. Although sticking strictly to the story the rabbit does this at the start and not the end, then goes to sleep.
Of course I may be reading too much into it, but the moral of the story is that you need to work hard from day one. When test time comes you shouldn't really be doing anything different. As a student (which I often am) I've even slowed down towards the end, not speed up!
I've seen this in my students also. If you get behind at the start, the pressure and workload prevents you from effectively being able to keep up with the current work and catch up from previous units.
Image taken from: http://wordsandmonsters.com/vflash
On top of this is the nature of learning. You need to constantly be reviewing and refreshing your memory. This is called many names such as the Learning Curve (which is the correct term from Ebbinghaus) or more recently in popular Education trends as Spaced Repetition.
The teacher tries to do this by reviewing the last lesson, unit tests, end of year tests, etc. But each student has their own strengths and weaknesses. You need to independently review the areas you are weak on throughout the year to ensure long term memory and success. This is one of the main advantages of videos online.