Harris,JohnR.,andMichaelP.Todaro.1970."Migration, Unemployment and
Development: ATwo-Sector Analysis." AmericanEconomicReview, 60(1): ì26-A2.
Thiswidelycitedpaperstartswiththepuzzlethatinpoordevelopingcountries
one observesindividualsmigrating fromagricultural areastourbanareas,even
thoughtheywouldhavepositivemarginal productinagriculture butfacea substantialprobability ofunemployment intheurbanarea.Thefirst stepintheexplanation
istonotethattherearepoliticallydetermined minimumwagesintheurbanareas
thatpreventwagesfromadjustingtoachievefullemployment forall thosewho
cometotheurbanareas.Theequilibriumdistribution ofpotential workers between
theruralandurbanareasequatesthemarginal productoflaborinagriculture tothe
expectedwageintheurbanarea,i.e.,theproductofthewageandtheprobability
ofemployment.