Over the last 3 months or so, my blitz rating on ChessTempo has varied from 1660 on up to 1700. Over the last couple of weeks, it's been hovering steadily in the 1680s and 1690s, with brief excursions into the 1700s.
I started to notice, even back in December, that as soon as I get into the 1700s, I drop back down to the 1680s and 90s. So I started tracking how many sub-1600 rated problems the server would dish to me each session. When I'm in the 1680s and 90's, about 50% of the problems are rated below 1600. As soon as I get into the upper 1690s and 1700's the number of sub-1600 rated problems goes down to about 25%.
This all makes sense ... as your rating goes up, the server dishes more "tougher problems" and conversely as your rating sinks, the server dishes out more "easier problems"
So my dilemma is focusing on minimizing misses of the 1600+ rated problems. What's going on is that as the number of sub-1600 rated problems decreases, the vacuum is filled with 1600+ problems.
I've also noticed that on those "additional" 1600+ problems that I end up missing, I miss because I think I see the answer fairly quickly, but I don't, so I end up moving pre-maturely (more quickly) instead of taking extra time for further analysis.
So I downloaded my history and did some cursory analysis.
Looking at problems from this year that I missed and that are rated greater than 1600 (215 total):
106 of them I ended up taking longer than the average solve time (by a whole minute).
109 of them I ended up taking less time than the average solve time.
So half of those misses on the 1600+ rated problems were due to moving too quickly.
Of those 109, the average solved time is about 45 seconds.
Of those 109, on average, I moved 20 seconds "too soon"
My conclusion: as I find my rating hovering in the 1690s, take a minimum of 65 seconds before I move, unless the solution is absolutely clear.
This analysis wasn't too serious, but I need to start playing with the data and thinking about these things now that I can download my entire history! :-)