Hello @EveG,
Welcome to the Klaviyo Community!
Have you tried performing these analysis in Google Analytics? Since you’re trying to track conversion based on an ad rather than an email, I would suggest using other third-party analytic tools to assist with this - such as Google Analytics.
Creating a segment in Klaviyo would be a great way to identify contacts who originated from that specific source/medium and made a purchase in the last 30-days. But it doesn’t speak to if that ad/source was the attributing source of the conversion or if there were additional factors. Depending on your goal this may be what you’re looking for.
Another thing to note, although by default we offer a 5-day attribution period for email (24-hours for SMS), this can be adjusted to however length of time you want. Additionally, though it’s typically a Placed Order event that’s used as a conversion metric, you can also adjust this to whatever event/metric you want.
I would recommend taking a look at some of our resources to further understand conversion and attribution within Klaviyo from the following Help Center articles:
I hope this helps!
David