Modelling: Big Questions Remain
Michael Batty's Blog
From Michael Batty's blog:
"Recently I was asked to speculate on what strides had been made in urban and transport modelling during the last 20 years and what did I think models would evolve to in the next 20. The current editorial in EPB summarises my thinking. In many senses, this was prompted by the oft-quoted sentiment that agent-based models of transport which build on many developments in the last decades including activity time budgeting, discrete choice and the ability of computers to handle many many objects through rapid computation, have not made the world better, but produced much inferior performances than earlier more aggregative model structures. For a while there has been the sneaking suspicion that aggregate models with all their limits in terms of representation, somehow generate more realistic predictions that their micro-dynamic equivalent, Of course there can be no true test as these model types are so different. However what is interesting is whether we can generalise in any way from the widest possible model experiences: as we add more detail and attempt to explain more, all other things being equal, are we more likely to get poorer or better predictions from comparable models? The implications is poorer although the jury is out because the evidence has rarely been assembled. This question remains unresolved, and probably will do so."