Typically RCM & RCE will help you understand the impact of individual programs, but that's probably not going to really answer your question in any reliable way. It will likely be difficult to get total clarity the impact of specific programs and combinations in isolation as a retrospective; most likely, you'll need to set up a specifically designed test to validate the anecdotal support.
Ideally what you want to do is create a test that validates the impact of specific combinations to test their impact on conversion/performance comparative to a baseline. Depending on your target audience size this may take time/be tricky, but I would look to create a series of target audiences that fall into different experimental groups, e.g.
- Control Group - Receives none or receives only nurture (option chosen depending on what you want the baseline comparison to be)
- Receives nurture + DM send
- Receives nurture + vidyard follow up
- Receives DM + vidyard follow up
- Receives nurture + DM + vidyard follow up
That's a lot of sub groups to test, so you'll need a reasonably sized data set to be able to get significant results. And for the test to really work, the experience of each tactic should be identical across all groups - your test is the presence/absence, not variations within each tactic. But a test like this would help you understand:
- What the baseline conversion is
- How specific marketing tactics impact that baseline
- How different combinations of marketing tactics impact that baseline.
Hope that helps.