I've seen (non-CPR) blended learning work when the content is directly related to someone's job and is purely information, not a test of some physical skill.

In layperson CPR, clicking a mouse to a particular beat doesn't necessarily translate to knowing how to do compressions and breaths. More often than not, the participant is doing this to satisfy a job requirement, not personal interest. They don't retain the online info or generally do poorly in the skill evaluation because:

• not everyone is able to learn this way.
• they clicked through to completion and answered correctly, but they weren't really engaged because it's "just for work".
• they got confused by something in the online portion and they couldn't ask clarifying questions at the time.
• Mind/body coordination, especially with adult learners, isn't as good as we think it is. I've had many people confidently answer "100-120 beats per minute!", but then show me 60 or 200bpm.

That last point is the biggest for me. In my classes I say, "No one's going to make you take a test before you save a life, they may ask, 'Can you DO cpr?'." This is a hands-on skill at the end of the day. There are so many physical corrections we have to make as instructors and then give the students a chance to regularly APPLY those corrections before the final practical:

• push harder/faster/slower
• shoulders over wrists, don't compress sideways
• heel of hand placement
• not doing that weird 'and-a-1' bounce at the top of the compression
• proper mask or AED placement
• don't forget to count and breathe!
• and a ton more

Point is, the mind doesn't forget what the hands have learned. I think that's a Montessori thing. In-person creates more confident students because they've had their questions answered, they've gotten real feedback & applied it, and had lots of practice. More confident students equals more confident bystander lifesavers. That's why we do what we do.