Please look at Lead Scoring in docs.marketo.com and the Definitive Guide to Lead Scoring. It sounds like none of this has been setup yet.
I don't mean Lead Scoring. This is more for a list of leads tied to a program/campaign. For example, if we had a lead list from an event, this rating system would show certain criteria- budget, authority, need, timeline etc. by way of rating them hot, warm, etc. I assume that this would involve Marketo at the point of list loading and if so, we are trying to figure out what fields to use and approach to take, specifically with Marketo and SFDC so Sales can report on which leads were the most important from certain campaigns.
This is a lead scoring program because you'd have to create a smart list like
Hot Leads = XYZ
Med Leads= ABC
Low Leads = not above. or whatever
then change data value: Ranking=Hot
so you need a new field Ranking=String type in both systems.
then create the smart lists and workflow.
When should this occur? Every day? Immediately?