Need help deciphering calculated field

Hi all, Our WF consultant created the calculated field below on our request form, and I'm trying to re-create it but can't figure out what the "LEN ... -2" does/means. The below calculation displays all the Digital Project Types and Design-Print Project Types a requestor selects (these are two separate custom forms, and requestors can select multiple deliverables under each): LEFT(CONCAT(IF(!ISBLANK(Digital Project Types),CONCAT(Digital Project Types,", "),""), IF(!ISBLANK({Design-Print Project Types}),CONCAT({Design-Print Project Types},", "),"")), LEN (CONCAT(IF(!ISBLANK(Digital Project Types),CONCAT(Digital Project Types,", "),""), IF(!ISBLANK({Design-Print Project Types}),CONCAT({Design-Print Project Types},", "),""))) -2 ) If I delete the "LEN ... -2)" calculation, nothing displays in the field. Conversely, if I delete the calculation preceding the "LEN" calculation, "0" displays. So I understand that both must be present to successfully show the list of deliverables the requestor chose, but I don't understand the reasoning behind it. I want to understand this calculation before I start re-creating it on other forms. Hope someone can break this down for me! Erica Lorenzo Writer-Editor BKD, LLP