Introduction. The social significance of official statistics -- The BLS and the underestimation of unemployment -- The CDC and the overestimation of life expectancy -- The FBI and the miscalculation of crime -- The census bureau and the decennial undercount -- Why official statistics matter.

The aim of this paper is to introduce a practical nonlinear generalization of PCA that captures nonlinear forms of dependence and delivers truly independent factors. The output of the method is a low-dimensional curvilinear coordinate system that tracks the important features of the data. The...