Table 1 Frailty defined by the public, statisticians and aging researchers

Laypeople

“The quality or state of being frail” (frail: easily broken or destroyed; physically weak) [9]

“The condition of being weak and delicate” [10]

Researchers/clinicians

The random effects that “account for association and unobserved heterogeneity” in statistical models [11]

“A state of vulnerability that becomes more prevalent with age and affects an individual’s resilience and ability to deal with minor and major stressors, which can include illnesses or infections” (National Institute on Ageing definition) [3]

“A clinical syndrome characterized by declining reserve and diminished resistance to stressors” (expert consensus) [12]

“A phenotype, which is defined as an individual’s observable traits that result from the interaction of their genetic information with their physical environment.” (Phenotype Model) [3]

“An accumulation of deficits, which can be physical, cognitive, and clinical challenges an individual may be facing, including falls, changes in the ability to carry out everyday activities, depression, restlessness, memory changes, and congestive heart failure—the more deficits an individual has, the greater their level of frailty” (Accumulation of Deficits Model) [3]