Também semana passada, a Economist publicou uma matéria sobre o mesmo assunto, avaliando o desempenho das projeções feitas pelo FMI. Os resultados também não são muito animadores, como se pode ver no gráfico:
Se projeções e previsões, no geral, erram tão feio, por que ainda há um mercado para elas? Para Tim Harford, projeções são como Pringles: "nobody thinks that there’s any great virtue in them but, offered with the fleeting pleasure of consuming them, we find it hard to resist." Por que? As teorias de Harford:
Possibility one is that the moment we hear a forecast, we imagine it happening. It then becomes a believable outcome and one that is easy to call to mind in the future. The scenario that we imagine looms large in our minds; other scenarios, equally plausible, fade to the background. As a result, we can be sceptical of forecasts in general yet still hooked by a particular one.
(...)
Possibility two is that forecasts offer us a lazy way to understand a complex world. The background to the conflict in Syria is complicated. So is Chinese politics. So, too, is the evolution of the Japanese economy. Trying to understand what is going on in any of these places requires an investment of time and attention that most of us are not willing to make. Wise heads at this newspaper could explain the intricacies to you or to me for hours yet barely have begun to do the topic justice.
Sobre o assunto, ainda quero ler o Superforecasting, sobre o Good Judgment Project.
