Cluster randomised evaluation of a training intervention to increase the use of statistical process control charts for hospitals in England: making data count.

Background: The way that data are presented can influence quality and safety initiatives. Time-series charts highlight changes but do not clarify whether data lie outside expected variation. Statistical process control (SPC) charts make this distinction and have been demonstrated to be effective in supporting hospital initiatives. To improve the uptake of the SPC methodology by hospitals in England, a training intervention was created. The current study evaluates the effectiveness of that training against the background of a wider national initiative to encourage the adoption of SPC charts.

Methods: A parallel cluster randomised trial was conducted with 16 English NHS hospitals. Half were randomised to the training intervention and half to the control. The primary analysis compares the difference in use of SPC charts within hospital board papers in a postrandomisation period (adjusting for baseline use). Trainees completed feedback forms with Likert scale and open-ended items.

Results: Fifteen hospitals participated across the study arms. SPC chart use increased in both intervention and control hospitals between the baseline and postrandomisation period (29 and 30 percentage points, respectively). There was no statistically significant difference between the intervention and control hospitals in use of SPC charts in the postrandomisation period (average absolute difference 9% (95% CI -34% to 52%). In the feedback forms, 93.9% (n=31/33) of trainees affirmed learning and 97.0% (n=32/33) had formed an intention to change their behaviour.

Conclusions: Control chart use increased in both intervention and control hospitals. This is consistent with a rising tide and/or contamination effect, such that the culture of control chart use is spreading across hospitals in England. Further research is needed to support hospitals implementing SPC training initiatives and to link SPC implementation to quality and safety outcomes. Such research could support future quality and safety initiatives nationally and internationally.

Trial registration number: NCT04977414.