Recently we've been working to refine and overhaul our Ratings systems to make it a more useful metric across all areas of the database. Previously we had only been able to display the Global Rating for any given waterfall on any list page, and for those waterfalls which didn't quite meet the cut off point to allow them to qualify to be rated globally, there simply wouldn't be any Ratings data shown on the various list pages. This has been changed so that the Ratings column shown on all list pages is now localized to the Country or Region that the list applies to specifically. So when viewing the list of Waterfalls in the United States, all of the Ratings presented (where available) will be based on the scale for the United States only. Likewise for individual States or Provinces or other such first-level geopolitical subdivisions.
In addition to this change, we've been able to work towards unifying all of the various disconnected calculations used to determine the Ratings numbers displayed on the various parts of the site so that it should be a more automated process now. The bugs should mostly be worked out, but there may be some cases where the numbers won't quite look right (negative numbers may show up once in a while). If you see such a case, we would appreciate being notified so we can add it to the list of issues to address. In following, because of situations where these negative numbers may appear, we plan on conducting a full audit of all our Ratings data in the next year to ensure that the data is actually accurate - we've already noticed some aberrations that need to be corrected, but the exact method for correcting them will probably require some internal discussions. There is a good chance that we may end up overhauling the entire Ratings calculation in the future as a result.