Why are USCF quick ratings lower than USCF regular ratings? I noticed that my USCF quick rating is lower than my USCF regular rating.  At first I thought maybe it was because I was relatively weaker at faster time controls, but it seemed like the difference was too large to be just that.  This got me to looking at the ratings of everyone in my section (It was the open section, there was another section of sub-1200 and unrated) of my most recent dual-rated tournament.  On average, the pre-event quick ratings of the 50-ish players in this tournament were 170 points below their regular ratings (and that even includes one player who never played quick before and was therefore given a provisional quick rating equal to his regular rating.)

It occurred to me that maybe I'm just in an area with local weirdness in the ratings, but that doesn't seem to be the case.  Wesley So has the highest regular rating in the nation, but his quick rating is 166 points lower than his regular.  The 100th best regular rating is 2474, but the 100th best quick rating is 2263, which is 211 points lower.

Although I know the player pools of the two rating systems are not identical, it would seem that the pools have significant overlap - all are USCF members who play in tournaments.  Initial quick ratings are literally based on the regular rating, if the player was already regular-rated.  And both rating systems appear to use the same algorithm to calculate ratings.

But despite that, quick ratings are significantly lower, apparently by nearly a full class.  Why are they so much lower, given the same algorithm and many of the same players?  And, assuming it's desirable that the ratings be similar, what could be done to correct this situation?
This may be partially due to ratings floors.

When a player hits his rating floor, his rating cannot go lower if he loses, but his opponent's rating can still go higher.  This adds ratings points into the system.

There is an absolute rating floor of 100 which nobody can go below. (For every event you play in and quarter-point you win over the board, this is raised by 1, to a maximum of 150.) Rating floors exist at every 100 points from 1200 to 2100, and these can be achieved by getting a rating at least 200 points above the floor. There's a rating floor at 2200 which can be earned by getting the Original Life Master title. And finally, if a player earns $4000 or more in an under-2000 section, their rating floor is set high enough so they become ineligible to win the prize again.

Regular and quick ratings both have ratings floors, but they are independent from each other. Most events with very large prizes are probably not quick-rated. And I don't think the Original Life Master title can be earned with a quick rating. This probably means that fewer people are at a floor with their quick rating, and that if they are, the floor is lower than it might otherwise be.  

To add rating points to the system, it is insufficient for a player to simply be at the floor - he must actually play games.  I would hypothesize that more regular-rated games are played than quick-rated games, especially at the 1200+ level where floors come into play.  I would also hypothesize that older players are more likely to be at a floor (because they won a large prize sometime on their life, because they once managed to raise their rating beyond its ordinary level, or because their skills are not what they once were) and that older players in particular play more regular games than quick games.

And if younger people play relatively more quick games, that may be another reason why quick ratings are lower.  Younger players are more likely to start with a very low rating but be rapidly improving.  When a player's ability improves, his rating lags behind, and his opponents will tend to lose rating points.  This tends to have a deflationary effect on ratings.