in this paper, we tested the catching up hypothesis toward USA using Becker et al. (2006) flexible Fourier KPSS stationary test over the period 1960-2009. The mentioned test could control for unknown number and form of structural breaks using a selected frequency component of a Fourier function. Our results show almost poor countries stay poor and almost rich countries stay rich. South Korea, Hong Kong, Singapore, Taiwan, India, Malaysia and China could escape lag deadlock and the countries like Central African Republic, Congo, Cote d`Ivoire, the Gambia, Guinea, Haiti, Kenya, Rwanda, and Senegal diverged from USA and moved into poverty trap.
