Supplier integration into new product/process/service development suggests that suppliers are providing information and directly participating in decision making for purchases used in the new product/process/service. This integration can occur during idea generation, preliminary business/technical assessment, product/process/service concept development, product/process/service design and development and prototype build, test or production ramp up.
Source: Handfield, R.B., Ragatz, G.L., & Monczka, R.M. (1999). Involving suppliers in New Product Development. California Management Review, 42(1), 59-82.