I have a situation where we are working with several different online ads/content syndication vendors. These programs run quarterly (sometimes more if they finish the program sooner), and I am having trouble figuring out how to check if the vendor already sent that lead in a previous campaign with ran with them. So for example, we are running a program with XYZ company in the month of Novemeber and December. They said in November we sent X amount of leads (which matches), but then in December they sent another X amount of leads. However, for the December campaign they're saying they delievered (for example purposes 200 leads), and we only have 180 on our end. How do I check those 20 leads that are not in our system? Which filter would help me figure out these 20 leads? Better yet, what filters would you use in general to find out how many leads came in from a certain time frame?
How are the leads being delivered? If they are through a form fill out and you have a specific form/page used by that vendor, you could just run a smart list: -"Filled Out Form" between Dec 1 - Dec 31 and that would show you all the leads who came in through that form.