 While it is helpful to ask what might be the most adverse consequences of any decision taken, possible tail outcomes need to be balanced in a judicious and pragmatic way against more likely outcomes. 8  All speeches are available online at www.bankofengland.co.uk/news/speeches  8  I see these elements as being embodied in the so-called risk management approach to the formulation of monetary policy, which has been embraced by many central bank policymakers.17  At a practical level, in recent years this approach has acknowledged the need for monetary policy to be cognisant of uncertainties and risks stemming from (say) the lower bound on policy rates or the threat of a liquidity trap, while at the same time recognising that policy considerations cannot ignore the implications of decisions should the trap be avoided and inflation rise over the medium term. 18  The former aspect of risk management has justified a more aggressive response to downside shocks to price stability as the lower bound drew closer. Our discussions in the MPC now also address the latter aspect of the risk management approach: how policy should evolve as inflation rises and those asymmetric risks stemming from the lower bound recede. In undertaking this discussions, the risk management approach entails judgement and pragmatism. Engineering is not enough. The inevitable subjectivity of these judgements re-introduces some art into the science of monetary policy.
The process runs as follows: Domestic interest rates at the longer end of the maturity spectrum tend to become more closely correlated with the global rate, or the rate of the largest trading partner, and less correlated with the domestic policy rate. This means that monetary transmission tends to go increasingly through the exchange rate channel, which is only a problem, however, if the exchange rate behaves badly. Unfortunately, there is a lot of evidence to suggest that it does. Uncovered interest rate parity (UIP) does not hold except over long horizons. Interest rate differentials give rise to widespread carry trading, which is by nature a bet against UIP. Exchange rates  BIS central bankers’ speeches  1  thus diverge from fundamentals for protracted periods, followed by sharp corrections. So the exchange rate often seems to be as much a source of shocks and instability as a tool for adjustment and stabilisation. Ultimately, these cycles can take the boom-bust form and, in extreme cases, can result in serious financial instability or crisis. The research on this phenomenon is still ongoing, but there is a lot of evidence to suggest that the problem would not disappear even if macroeconomic policies in the traditional sense were perfect. This process was important in the Icelandic episode. The capital inflows were driven by the traditional push and pull factors.