Tactics Trainer

This may be a very embarassing question, but about 3-4 weeks ago my Tactics Trainer rating was solidly in the 2000's range.  I would float up and down about 100 points depending on how fresh I was at the time I was solving the puzzles, but it was consistent.  Then all of a sudden it seemed like the puzzles started getting harder.  I would see evidence from the comments that the puzzles I was trying to solve used to be ranked a lot higher, but they were slowly working their way down in rating.  I'm now bouncing between 1600 and 1700.  Have the puzzles / ratings become more difficult recently?  Or have I just lost it?

I think dpruess said the other day that the problems have had their ratings lowered, so I suspect that you are right that the problems being served are suddenly harder.

As a 1300 rated tactic trainer i can not say much but do not feel bad.I once had a rating of 1608 in online chess which came down to 1454.I didn't lose hope and i'm now 1558-not bad huh?

I've also noticed that the level adjusts itself to my rate of success - as if to say, "OK, let's go on to the next level" - or failure, indicating "let's return to some basics." That's just fine with me.