French to English Tech/Engineering Engineering (general)

My ST has so little context it's not worth quoting, but given its provenance I'd say that the term being used is the same as its use in this more contextually-useful sentence:
"Mais l’évaluation du PIB est problématique. On connaît, aux erreurs statistiques près, sa valeur : c’est l’écart entre la valeur de la production et celle des matières premières et produits intermédiaires consommés pour produire. "
(from http://www.volle.com/opinion/croissance2.htm)

Looks like there should be a 'standard' English translation for the term but I'm struggling to find it!

Any input appreciated, thanks