[manifold]

It's not perfectly linear in the short term, though what tends to happen is a longer-term cyclical effect rather than spikes.

This makes sense - medical advances won't be widely adopted immediately, then there will be a gradual acceleration of adoption (and improvement rate) once its benefits are proven and costs come down, and then no further contribution to improvements once wide adoption is the norm.

What you also tend to see is that advances affect improvements by year of birth more prominently than by year of discovery. In the UK we have a 'golden cohort' for example, which you could Google for more info.

Spikes do tend to occur during and after big causes of death (spanish flu, world wars) as the improvement rate drops sharply and then recovers again.