[A. Pole]

Well, I guess a physicist should be able to predict economic trends at least as accurately as an economist.

He should much better as he is not blinded by an ideology (of free market or socialism or else). Physicists deal with various, complex, often not related phenomenons. Earthquakes indeed might be harder to predict.

[B.Bumbleberry]

All of these efforts rely on the false assumption that the future can be predicted by examining the past, and the erroneous belief that complicated mathmatical models can bring certainty to something that is inherently uncertain--the future economic decisions of millions of people. The study of future markets is behavioural science, not mathmatical science. So yes, a physicist can predict economic trends as accurately as an economist, which is to say, neither can.