R&D in products is often clearly separated from production and sales of the products. R&D can happen in isolation from other aspects of the operations, and also in isolation from customers.
An engineer and industrial designer can design a new toy without meeting a single child (customer). After the toy goes to market, feedback will eventually trickle back from the market. This then triggers the next R&D or improvement cycle, done in isolation from customers.
Because of the clearly delineated stages in the linear value chain, value is fairly straightforward to measure, in terms of ROI.
R&D in service design is often invisible because it is bound up in the delivery of the service. It is not possible to conduct R&D for services in isolation from customers because the delivery, feedback and improvement are live and immediate.
Value is measured (primarily qualitatively) by the quality of the customer experience. ROI is harder to calculate because is difficult to compartmentalise development and consumption within the value net that is service delivery.
Services are also exportable. It is the third largest growing export in Sweden. Do you run a services company? Maybe you need to think about exporting that?!
(From a talk by Eva-Karin Anderman at the Innovation and Service Design conference, 29 Jan 2010, Malmö, Sweden. Diagrams are mine.)