Does that metric include the delay if fixes getting incorporated into Linux distributions (and pushed out, assuming automatic updates—maybe not a good assumption) or Windows fixes getting deployed via Windows Update?
Edit: I don’t know much about this topic, but thought “time to deployment of a fix” might be more useful. Edit again: also unclear if the comparison is “apples to apples”.
The dataset does not appear to discuss the lifecycle of Linux distributions taking the security patches from upstream, nor the update process for all of the downstream distributions.
Something that's been widely discussed elsewhere is how often security issues are silently fixed in Linus's repo and therefore not picked up by distributions for their stable/LTS releases.
I buy the immediacy of patches if you compile your own kernel from the latest kernel.org sources, not if you're relying on distributions.
The dataset is quite small, but on average it took Linux 25 days to fix a 0-day while it took Microsoft 83 days.