You could use an exclamation mark icon that shows a tooltip on hover to explain exactly, what it means and what is missing / what value is bad:

^{download bmml source – Wireframes created with Balsamiq Mockups}

You could use an exclamation mark icon that shows a tooltip on hover to explain exactly, what it means and what is missing / what value is bad:

^{download bmml source – Wireframes created with Balsamiq Mockups}