Models of aggregate productivity growth linked to sectoral models of produc
tion typically assume that product and factor markets are perfectly competi
tive. The perfect markets assumption allows intermediate goods to be viewed
as internal, offsetting transfers. This paper relaxes the conventional per
fect markets assumption. The: alternatives of basing aggregate models of pr
oductivity growth on value-added versus delivery-to-final-demand frameworks
are analyzed. The import;ml finding is that if imperfect markets exist, th
en the value-added and tilt: delivery-to-final-demand models generate ident
ical measures of aggregate productivity growth only under very restrictive
assumptions; moreover, a simple variant of imperfect competition cannot rec
oncile these productivity measures.