Večkrat sem že pisal o tem, da je ekonomija z nekaj predpostavkami poenostavila realni svet in ga naredila predvidljivega. Če predpostavite racionalnega posameznika z racionalnimi pričakovanji in nato te individualne subjekte preprosto združite (seštejete) v gospodinjstva in podjetja, vas nič ne more presenetiti. Resda lahko posamezni subjekt “gre po svoje”, toda v povprečju, v agregatu, se ta stohastika, te individualne anomalije (po predpostavki) med seboj izničijo in dobite predvidljiv svet, kjer posamezniki na podlagi optimizacijskega obnašanja svet vedno znova zavrtijo v optimalno ravnotežje. V tej “ekonomski deželi” ni prostora za “slabe dneve”, menstrualne vplive in drugačne neracionalne odzive posameznikov, ki bi v interakciji z drugimi subjekti tok dogajanja obrnili povsem v drugo smer od začrtanih optimalnih odločitev. Še manj pa je prostora za velika naključja, za “strele na Franza Ferdinanda”, ki bi preokrenili tok zgodovine.
Seveda je to samo fikcija, ekonomska pravljica, pravljična “dežela Nije”, v katero pa makroekonomisti zadnjih 40 let večinsko absolutno in dogmatsko verjamejo. No, ne vsi. Alan Kirman je v zadnjem OECD Insights to dogmatsko verovanje lepo pokritiziral. Povedal je, da – za razliko od drugih znanstvenih ved – samo ekonomisti zanikajo kompleksne adaptivne sisteme, kjer se tok zgodovine oblikuje na podlagi kompleksnih interakcij med posamezniki, ne pa na podlagi šablonskega mehaničnega obnašanja posameznikov, ki optimizirajo svoje odločitve v izolaciji eden od drugega. Če predpostavljate tak pravljični svet z izoliranimi racionalnimi posamezniki, ga seveda ne morete razumeti, kaj šele predvideti in napovedovati bodočega dogajanja.
Over the last two centuries there has been a growing acceptance of social and political liberalism as the desirable basis for societal organisation. Economic theory has tried to accommodate itself to that position and has developed increasingly sophisticated models to justify the contention that individuals left to their own devices will self organise into a socially desirable state. However, in so doing, it has led us to a view of the economic system that is at odds with what has been happening in many other disciplines.
Although in fields such as statistical physics, ecology and social psychology it is now widely accepted that systems of interacting individuals will not have the sort of behaviour that corresponds to that of one average or typical particle or individual, this has not had much effect on economics. Whilst those disciplines moved on to study the emergence of non-linear dynamics as a result of the complex interaction between individuals, economists relentlessly insisted on basing their analysis on that of rational optimising individuals behaving as if they were acting in isolation.
Yet this paradigm is neither validated by empirical evidence nor does it have sound theoretical foundations. It has become an assumption. It has been the cornerstone of economic theory although the persistent arrival of major economic crises would seem to suggest that there are real problems with the analysis. Experience suggests that amnesia is prevalent among economists and that, while each crisis provokes demands for new approaches to economics, (witness the birth of George Soros’ Institute for New Economic Thinking), in the end inertia prevails and economics returns to the path that it was already following.
There has been a remarkable tendency to use a period of relative calm to declare victory over the enemy. Recall the declaration of Robert Lucas, Nobel Prize winner and President of the American Economic Association in his Presidential Address in 2003 in which he said: “The central problem of depression-prevention has been solved.”
Both economists and policy makers had been lulled into a sense of false security during this brief period of calm.
Then came 2008 and, as always in times of crisis, voices were raised, mainly by commentators and policy makers enquiring as to why economists had anticipated neither the onset nor the severity of the crisis.
As soon as one considers the economy as a complex adaptive system in which the aggregate behaviour emerges from the interaction between its components, no simple relation between the individual participant and the aggregate can be established. Because of all the interactions and the complicated feedbacks between the actions of the individuals and the behaviour of the system there will inevitably be “unforeseen consequences” of the actions taken by individuals, firms and governments. Not only the individuals themselves but the network that links them changes over time. The evolution of such systems is intrinsically difficult to predict, and for policymakers this means that assertions such as “this measure will cause that outcome” have to be replaced with “a number of outcomes are possible and our best estimates of the probabilities of those outcomes at the current point are…”.
Consider the case of the possible impact of Brexit on the British economy and the global economy. Revised forecasts of the growth of these economies are now being issued, but when so much depends on the conditions under which the exit is achieved, is it reasonable to make such deterministic forecasts? Given the complexity and interlocking nature of the economies, the political factors that will influence the nature of the separation and the perception and anticipation of the participants (from individuals to governments) of the consequences, how much confidence can we put in point estimates of growth over the next few years?
While some might take the complex systems approach as an admission of our incapacity to control or even influence economic outcomes, this need not be the case. Hayek once argued that there are no economic “laws” just “patterns”. The development of “big data” and the techniques for its analysis may provide us with the tools to recognise such patterns and to react to them. But these patterns arise from the interaction of individuals who are in many ways simpler than homo economicus, and it is the interaction between these relatively simple individuals who react to what is going on, rather than optimise in isolation that produces the major upheavals that characterise our systems.
Finally, in trying to stabilise such systems it is an error to focus on one variable either to control the system or to inform us about its evolution. Single variables such as the interest rate do not permit sufficient flexibility for policy actions and single performance measures such as the unemployment rate or GDP convey too little information about the state of the economy.
Vir: Alan Kirman, OECD Insight