The criteria for deciding who should be considered an inventor are, for example, quite different to those normally applied to determining authorship of a scientific research paper. Although there are no actual rules laid down in law, the following is the approach generally applied in the UK:

Firstly it is necessary to define the invention (or inventions) which form the basis of the patent application. Generally speaking, an invention could be a new material or apparatus, or method or process, which is properly described in the application. This can be assessed by comparing experiments, data or ideas disclosed in the patent application with previously published technology.

Secondly, once each invention is defined, it is necessary to decide who actually devised it. Generally speaking this may include anyone who:

• Conceived the initial ideas which defined the research which leads to the invention.
• Actually devised the experiments or materials which form the basis of the patent application.
• Carried out any experiments or other processes which are described in the patent application and which required that person to show initiative to complete, for instance because unexpected practical difficulties had to be solved.
• Interpreted the data disclosed in the patent application, particularly if the data was unexpected, or its significance was initially unclear.

An inventor is someone without whose intellectual contribution the invention in its current form would not have been made.

It is unlikely to include anyone who:

• Simply carried out work under instruction (regardless of how much skill and effort this took) particularly if the work took no initiative and required no modifications to carry out as instructed.
• Had no part in the research, regardless of whether or not they funded it, or were associated with it in other ways, or owned the facilities which were used in the research, or published earlier relevant work, or contributed very general work or assistance.
• Has been a Project Manager or Supervisor but did not contribute intellectually to the actual invention.