The half life of a coffee is about 6 hours. If you ingest one at 6pm, half the caffeine and half the effect is still circulating in your bloodstream at midnight.

Leaving aside the idea that there is a half life of knowledge (you can read more about that here) what I am interested in is the concept that educational ideas, despite being implemented with verve and enthusiasm, usually decay in effect.  

So, in schools, we might decide to implement a policy of staff saying hello to children every morning to brighten everyones’ day, only to find that 6 weeks later the effect has worn off, and only half the people are doing it.

At CST, we’ve worked hard to minimise the decay effect.  Our solution, which may not be the only one, is to define what we want (with high expectations), design a checking system, and make someone responsible for looking after it.  It’s not perfect (there’s lots to do in schools, with limited time and resources, in case you hadn’t noticed) but it seems to work better than the alternative.