Our campaigns have specific goals created when clients pay for event tracking which tracks actual form fill-out submissions and phone call clicks. The goals might vary depending on the management or ownership group but are typically a good indication for tracking audits.
0 Conversions typically mean tracking needs to be reviewed. There could be goal updates needing to be implemented like a form being removed from the website or potentially one of our tracking tags being removed.
A high amount of conversions (ie 120) typically means there might have been an automated goal added to the campaign by Google that needs to be removed. There are times also when an update might be making the tag misfire.