such historic change. fundamental structural economic change invariably produces economic victims. the temptation for governments to interfere excessively with the free market is therefore particularly acute during periods when dramatic change occurs. paradoxically, it is precisely then that the forces of the “ invisible hand ” are most needed to help bring about the welfare that can ultimately help absorb the negative externalities of change. if i am right that we are currently traversing such a period of historic change, it is more important than ever to ensure that government intervention in markets is limited and remains subject to continuous checks. free markets under the rule of law, ladies and gentlemen, provide the optimal path to welfare creation and ultimately responsible behaviour by market participants. as the history of the industrial revolution which began shortly after adam smith ’ s death demonstrates compellingly, there will always be people who endure great difficulties when rapid economic change occurs. chairman greenspan has recently noted that “ a significant minority, trapped on the adverse cycle of the market ’ s process of creative destruction, are suffering. this is an issue that needs to be more fully addressed if globalization is to sustain the public support it requires to make further progress. ” perhaps this will indeed be one of the major challenges we will face in the years to come. dealing with it by way of relentless government interference with the forces of the free market will at best fail to produce desirable results. at worst, it will begin to reverse the dramatic welfare gains we have enjoyed since the time of adam smith.

the fact that inflation dynamics have been tepid indicates that historical averages may not be an appropriate benchmark for today ’ s policy stance and that corresponding benchmark levels must have fallen. policymakers need to be wary of these trends. they are probably rooted in receding growth rates in potential output and the legacy of financial factors that have emerged in the wake of the financial crisis ( like risk aversion and deleveraging pressures ). the degree of monetary policy accommodation, based on various real return measures, needs to be assessed relative to these benchmark trends in real yields. certainly, if these slow - moving trends in real yields are also taken into account, the current level of real interest rates provides an ample degree of policy accommodation. but interpreting their present levels against the background of their protracted downtrend and persistently subdued inflation underpins our stance that we have to be prudent, patient and persistent in calibrating our policy, as inflation will probably converge only gradually towards our objective. looking ahead, monetary policy will evolve in a data - dependent and time - consistent manner. once the governing council judges that the three criteria for sustained adjustment – convergence, confidence and resilience – have been met, net asset purchases will expire, in line with our guidance. from that point in time, inflation developments will remain conditional on reinvestments continuing for an extended period of time and on policy rates remaining at their 3 / 4 bis central bankers'speeches present levels well past the end of our net asset purchases. the stock of long - duration assets held in our portfolio will continue to put downward pressure on longer - term interest rates well beyond the end of our net purchases. policy rates remaining at their present levels well past the end of our net purchases will contribute to holding the short to intermediate portions of the yield curve in check for as long as necessary, thereby ensuring that financial conditions remain consistent with a sustained adjustment of inflation. see, for example, the european commission ’ s “ european economic forecast – autumn 2017 ”. potential growth was estimated at 1. 4 % for 2017 and 1. 5 % for 2018 and 2019. 2 for more details, see the box entitled “ the targeted longer - term refinancing operations : an overview of the take - up and their impact on bank intermediation ”, economic bulletin, issue 3, ecb, 2017. 3 see the ecb ’ s euro area bank lending survey, january 2018, and the ecb ’ s