>The Scottish Patient Safety Programme (SPSP) is a national initiative which aims to improve in‐hospital mortality rates in Scotland. The SPSP was established in 2008 and had perioperative management, including implementation of the WHO surgical checklist, as one of its four key initial workstreams. This programme offered a systematic approach to improve patient safety across all hospitals in the country26.

>After testing, review and feedback from health boards across Scotland, the surgical checklist was included as one of the ten Patient Safety Essentials to be implemented across all health boards in Scotland37. The surgical checklist was not a stand‐alone intervention. It was, however, the only Patient Safety Essential that targeted surgical patients specifically during the interval studied37. Thus, the addition of the checklist to the other parameters within the SPSP may have contributed to the improvement in results observed in the present study.

>It is acknowledged that attributing causal links to the findings in population‐wide data set analysis is not possible.

What you said they didn't do is kind of exactly what they did. Yes, there is some attempts at hand waving, but it's silly to boil down the success of a large and multi pronged program to a simple checklist.