In this paper I apply the nonparametric methods proposed by Quah to data on
US state relative income levels. In contrast to Quah's results using cross
-country data I find no evidence of polarization in the cross-state income
distribution. The long-run density implied by the estimates is strongly uni
modal. This finding is consistent with the results of previous analyses of
convergence in state income levels using other methods. (C) 2000 Elsevier S
cience S.A. All rights reserved.