Why is hitting A&E time targets so hard?: using Nudge theory and modelling to improve response times

Abstract

Aims

To improve the one hour response times to referrals made to psychiatric Liaison in A&E without adding or changing available resources.

Method

Response time data of referrals made to the Homerton University Hospital psychiatric liaison service was collected dating back from August 2016 to October 2019 (n = 10225).

A nudge was introduced in the form of a large display showing referrals arriving in real time in the staff office.

Data was then collected over a period of 5 weeks (n = 436) to measure if any change had occurred in response times.

Result

Response times appear to follow a Poisson like distribution curve. The average referral was responded to within 6 minutes (n = 1577) prior to the nudge, and 6 minutes (n = 88) after. Prior to the nudge the 95% referral envelope fell within 134 minutes (n = 9728) and was 122 minutes (n = 414) after the intervention. Significant statistical difference is observed upon considering response in the first 240 minutes.

Conclusion

Nudge interventions could be a useful resource-sparing method to improve services. The average referral to the HUH liaison team was quickly responded to within 6 minutes and yet hitting the 1 hour 95% target appears ever-elusive. Hitting targets of 95% responses within 1 hour may prove very difficult if we are not considering natural distributions, such as Poisson, occuring in the backgroung which ultimately may require a change in approaches to how we set performance targets.