Perception is everything

True story. We have been working for a fixed income trading desk that officially (from a management's perspective) uses a homegrown processing system for its positions, P&L, and back office processing. This system can provide intra-day positions and P&L upon request, but the traders have never (meaning over years) believed the numbers this system produces and so have not used it. Worst still, they **guess** their positions and P&L during and at the end of the day, and can often be $0-1mm out in their guesses.

We have been working on a number of projects for this business where are are doing a mix of RAD and tactical/prototypes for some new risk mgt tools for the traders. One of these prototypes pulls together a bunch of intra-day data from various sources, including the above mentioned system, does some aggregation and provides a rich and flexible front-end for position and P&L tracking (the server and client side is .NET, btw).

These traders think this tool is the best thing since sliced bread and think it is much better and more accurate than the old system they are/were supposed to use. How ridiculous is this ? Can you imagine a multi-million dollar a day business being run by people guessing their P&L, let alone thinking that the new sytem is better than the one they despise ...!!

PS. Not a bad argument for Agile development though, where users get what they want ..