Uncorrelated Risk and Complex Systems
June 2, 2009
An interesting article in the Wall Street Journal by the father of modern portfolio theory, Harry Markowitz, discussing the current financial crisis. He emphasises the need for diversification across uncorrelated risk as the key to minimising balanced portfolio risk, and highlights its lack as a major factor behind our present predicament. However to my mind this still begs a question of whether any risk can be truly uncorrelated in complex systems. Power law environments such as financial markets are defined by their interconnectedness, and the presence of positive and negative feedback loops which undermine their predictability. That interconnectedness makes identifying uncorrelated risk exceptionally problematic, especially when such correlations have been hidden inside repackaged derivatives and insurance products.
In systems that are intrinsically unpredictable, no risk management framework can ever tell us which decisions to make: that is essentially unknowable. Instead, good risk strategies should direct us towards minimising our liability, in order to minimise the cost of failure. If we consider “current liability” within the field of software product development as our investment in features that have yet to ship and prove their business value generation capabilities, then this gives us a clear, objective steer towards frequent iterative releases of minimum marketable featuresets and trying to incur as much cost as possible at the point of value generation (i.e. through Cloud platforms, open source software, etc). I think that is the real reason why agile methodologies have been so much more successful that traditional upfront-planning approaches: they allow organisations to be much more efficient at limiting their technology investment liability.