I didn't become interested in derivatives until 1982, 1983.
I think VAR is a very healthy development within the industry.
I guess any simple idea that is really good will catch on quickly.
Our starting point then was trying to find a way to incorporate mean reversion into the HoLee model.
Our research led on to other things, such as the fact that exchange rates are not lognormally distributed.
The problem with interest rates are that you are not modeling a single number, you are modeling a whole term structure, so it is a sort of different type of problem.
We started giving presentations at practitioner conferences in 1986, and since then all of our derivatives research has been stimulated by contact with practitioners.
There are challenges in terms of the measurement of VAR for what are known as nonlinear derivatives, where things like gamma and vega are important dimensions of the risk.
We concluded that you cannot rely on delta hedging alone. It sounds simplistic to say that now, but back then, this was the sort of thing people were only just beginning to realize.
When interest rates are high you want the average direction in which interest rates are moving to be downward; when interest rates are low you want the average direction to be upward.