The glossary explains some of the words used across this website and covers some key cancer and research terms, which primarily focus on lung cancer.

Quality-adjusted life year (QALY)

A standardised economic measure of an individual’s life expectancy and quality of life.1 One QALY is equal to one year a person lives in perfect health. QALYs are used to evaluate new interventions, such as low-dose computed tomography screening. Decision-makers may compare the net number of QALYs (health benefit) that a screening programme is expected to bring to a population against the projected costs to understand whether it is a cost-effective strategy to implement.2 See also ‘Disability-adjusted life year’ and ‘Cost-effectiveness analysis’


  1. National Institute for Health and Care Excellence (NICE). Glossary.  Available from: [Accessed 07/03/22]

  2. National Institute for Health and Care Excellence. 2012. The guidelines manual: Process and methods. London: NICE