Research and development intensity (R&D intensity) is generally defined as expenditures by a firm on its research and development (R&D) divided by the firm's sales. There are two types of R&D intensity: direct and indirect. R&D intensity varies, in general, according to a firm's industry sector, product knowledge, manufacturing, and technology, and is a metric that can be used to gauge the level of a company's investment to spur innovation in and through basic and applied research. A further aim of R&D spending, ultimately, is to increase productivity (e.g., factor productivity) as well as an organization's salable output.