Abstract
Background: The English National Health Service has multiple waiting time standards relating to cancer diagnosis and treatment. Such targets can have unintended effects, such as prioritisation based on targets instead of clinical need. If such an effect exists, a spike in the number of hospitals just meeting the target would appear, referred to as a `threshold effect’.
Approach: We conducted a retrospective study of publicly available cancer waiting time data for three key standards: 2-week wait for a specialist appointment, 31-day decision to first treatment, and 62-day referral to treatment standard that attracted a financial penalty. The study involved examining the performance of hospital trusts against these targets by financial year, using Cattaneo et al. manipulation density test to identify threshold effects.
Results: The analysis revealed a decline in trust performance against cancer waiting targets over time, with an acceleration of this trend since the start of the Covid-19 pandemic. While threshold effects for the 2-week and 31-day standards were only evident for a few years, there was strong statistical evidence of a consistent threshold effects for the 62-day standard across all financial years (p<0.01).
Implications: These findings suggest that threshold targets can significantly influence hospital behaviour, but not uniformly across all standards. The strong threshold effect observed for the 62-day standard highlights the need for careful consideration in designing and implementing healthcare targets. The difference could possibly be due to some combination of a smaller volume of eligible patients, a larger penalty, multiple waypoints where hospitals can intervene, baseline performance against the target and where the target is set (i.e. how much headroom is available). Future research, including randomised controlled trials, could explore alternative target designs to minimise the unintended consequences and ensure patient care is prioritised based on clinic need rather than meeting performance targets.