See data completeness in Drupal? I am using Drupal basically to store a ton of info on various topics. The problem is, we add data slowly over time. 

I would like to get a report that shows which nodes have the least content. I.e. The most empty fields. This way, I can tackle those with the least amount of data first. Is this possible with Drupal?
It seems you're looking for the Content Complete module 


  Content Complete is a CCK extension module that allows to tag CCK fields needed for completion (CCK Complete). The module checks the tagged fields against the content provided for those content types, and computes a complete percentage that can be shown to the user.


Image from the project page



Similar module is Field Complete


  In some situations you want to mark an entity field to indicate it should be completed but not enforce its completion at that time. This module extends the choice between Required and Not required to "desirable" completion.