  Pseudo panels constituted with repeated cross-sections are good substitutes
to true panel data. But individuals grouped in a cohort are not the same for
successive periods, and it results in a measurement error and inconsistent
estimators. The solution is to constitute cohorts of large numbers of
individuals but as homogeneous as possible. This paper explains a new way to do
this: by using a self-organizing map, whose properties are well suited to
achieve these objectives. It is applied to a set of Canadian surveys, in order
to estimate income elasticities for 18 consumption functions..
