This paper deals with the required conditions for the use of average wages (unit labour costs) as estimates of the true wage levels, when one wishes to use least square methods to evaluate substitutions between heterogeneous labour categories. We show that such practice induces measurement error...

Does migrants' experience abroad provide an earnings premium for wage earners and/or a productivity advantage for entrepreneurs? In terms of earnings, we find that experience abroad results in a substantial wage premium for migrants returning from an OECD country but not for other return...