Выражение встречается в следующем контексте:

While at the University of Groningen, Maddiston took the lead in stimulating production side studies utilizing unit values as the basis for PPPs

Because GGDC builds their estimates up from the production rather than the expenditure side, it requires the estimation of industry or sector-specific PPPs. The GGDC, in collaboration with the National Institute of Economic and Social Research (London), has undertaken several such studies making extensive use of producer-based unit values, obtained from manufacturing production censuses and industry surveys

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