The Research & Development Growth ratio is a measure of how quickly a company has grown its R&D expenditures. It is calculated as the year on year change in R&D expenditure. This is measured on a TTM basis.
Companies that are able to generate growth without investing significant amounts into are considered superior to those that are able to do so without investing significant amounts into it.
This is because more cash is available for return to shareholders in companies where spending requirements are low than in companies where the requirement is high.
This is measured on a TTM basis.