I understand in direct mail marketing some mail ends up undeliverable-as-addressed, but the
number of returned mail for my recent campaign is a lot. I was wondering, is there a rate
of undeliverable mail pieces that one expects in any campaign?

@moe Hi, what type of list did you mail to? What was the size of the list and how many came back? You must have mailed out first class to get the undeliverables back. Sometimes the ones that come back can be valuable to skip trace further and may indicate a distressed property. The general deliverability rate should be over 90%. Mailing lists should be NCOA certified before mailing.