Effect of a doctor working during the festive period on population health: natural experiment using 60 years of Doctor Who episodes (the TARDIS study)

OBJECTIVE: To examine the effect of a (fictional) doctor working during the festive period on population health.

DESIGN: Natural experiment.

SETTING: England, Wales, and the UK.

MAIN OUTCOME MEASURES: Age standardised annual mortality rates in England, Wales, and the UK from 1963, when the BBC first broadcast Doctor Who, a fictional programme with a character called the Doctor who fights villains and intervenes to save others while travelling through space and time. Mortality rates were modelled in a time series analysis accounting for non-linear trends over time, and associations were estimated in relation to a new Doctor Who episode broadcast during the previous festive period, 24 December to 1 January. An interrupted time series analysis modelled the shift in mortality rates from 2005, when festive episodes of Doctor Who could be classed as a yearly Christmas intervention.

RESULTS: 31 festive periods from 1963 have featured a new Doctor Who episode, including 14 broadcast on Christmas Day. In time series analyses, an association was found between broadcasts during the festive period and subsequent lower annual mortality rates. In particular, episodes shown on Christmas Day were associated with 0.60 fewer deaths per 1000 person years (95% confidence interval 0.21 to 0.99; P=0.003) in England and Wales and 0.40 fewer deaths per 1000 person years (0.08 to 0.73; P=0.02) in the UK. The interrupted time series analysis showed a strong shift (reduction) in mortality rates from 2005 onwards in association with the Doctor Who Christmas intervention, with a mean 0.73 fewer deaths per 1000 person years (0.21 to 1.26; P=0.01) in England and Wales and a mean 0.62 fewer deaths per 1000 person years (0.16 to 1.09; P=0.01) in the UK.

CONCLUSIONS: A new Doctor Who episode shown every festive period, especially on Christmas Day, was associated with reduced mortality rates in England, Wales, and the UK, suggesting that a doctor working over the festive period could lower mortality rates. This finding reinforces why healthcare provision should not be taken for granted and may prompt the BBC and Disney+ to televise new episodes of Doctor Who every festive period, ideally on Christmas Day.