OBJECTIVES: Studies to produce utility values for the EQ-5D-5L instrument are ongoing internationally. These include the valuation of 10 EQ-5D-5L health states using the time trade-off (TTO) method. In some of the studies carried out to date, relatively low mean TTO values for mild health states have been observed. It is hypothesised that this is because the health states under evaluation are being compared to “full health”, whereas in previous studies they were compared to 11111 (the “best” health state in the descriptive system). The objective is to assess differences in TTO valuations using two different comparators (full health and 11111). METHODS: Preferences for EQ-5D-5L health states were elicited from a broadly representative sample of the UK general public. TTO data were collected using computer-assisted personal interviews, carried out in respondents’ homes. Respondents were randomly allocated to one of two arms: in arm 1 the comparator health state was full health; in arm 2 the comparator health state was 11111. After completing 10 TTO valuations, respondents were asked follow-up questions which sought to examine their interpretations of the term “full health”.  RESULTS: