On Bródy’s conjecture: facts and figures from the US economy

Bródy’s conjecture is submitted to an empirical test using input-output flow data of varying size for the US economy for the benchmark years 1997 and 2002, as well as for the period 1998-2010. The results suggest that the ratio of the modulus of the subdominant eigenvalue to the dominant one increases both with the size of the matrix and, for the same matrix size, over the years lending support to the view of increasing instability (in the sense of Bródy) for the US economy over the period 1997-2010.