Pavitt's taxonomy consists of four categories of industrial firms:
(1) Supplier-Dominated: includes firms from mostly traditional manufacturing such as textiles and agriculture which rely on sources of innovation external to the firm.
(2) Scale-Intensive: characterized by mainly large firms producing basic materials and consumer durables, e.g. automotive sector. Sources of innovation may be both internal and external to the firm with a medium-level of appropriability.
(3) Specialized Suppliers: smaller, more specialized firms producing technology to be sold into other firms, e.g. specialized machinery production and high-tech instruments. There is a high level of appropriability due to the tacit nature of the knowledge.
(4) Science-based: high-tech firms which rely on R&D from both in-house sources and university research, including industries such as pharmaceuticals and electronics. Firms in this sector develop new products or processes and have a high degree of appropriability from patents, secrecy, and tacit know-how.