The Disputed Quality of Software Patents

Intellectual Property and Patents

Article Snapshot


John R. Allison and Ronald J. Mann


Washington University Law Review, Vol. 85, No. 2, pp. 297-342, 2007


Some claim that software patents are generally of low quality. However, empirical analysis shows that software patent quality is similar to that of other patents. There is no difference in the quality of software patents obtained by large firms compared with those obtained by small firms.

Policy Relevance

Patent reforms should not target software patents. Reforms that require higher quality patent filings would not harm small inventors.

Main Points

  • Large firms complain that low-quality patents obtained by smaller firms are impeding innovation, but systematic analysis of 34,000 software patents finds no evidence that software patents obtained by smaller firms are of lower quality than those obtained by larger firms.
  • These software patents show many objective indications of quality and value.
    • Software patents have more references to earlier patents (“prior art”) and claims, and are more often cited by future patents than patents obtained by the same firms on non-software inventions.
    • Software patents obtained by firms that make only software have more prior art references and claims, and are more often cited by future patents than software patents obtained by firms that sell other products.
  • Analysis of software patents does not support the view that software patents should be prohibited to reduce the number of low-quality patents.
  • Software patent applicants often describe the invention in duplicative ways, such as describing the invention as a “method,” a “device,” and a “system;” software patents are more likely than others to cite non-patented prior art.
  • Proposed patent reforms intended to increase the quality of patents overall include higher examination fees, special procedures for “gold-plated” patents, or additional opportunities for other inventors to oppose the grant of a patent.
  • Reforms intended to encourage inventors to better support their patent applications or to subject their applications to a more rigorous review would not unfairly burden smaller inventors.


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