I know I’m above average, because I was tested. I’m also chronically insecure enough to go around telling everyone.
If you’re talking IQ, then if the median is 100 with a standard deviation of 15, then I am above average but nowhere near the level of a lot of the people on this board.
I was made to take an IQ test when I was 12 (1992). For some reason it was the first step in determining if I was mentally unstable. According to my school records, I tested at 135. I have no idea how accurate that is because I frequently feel completely deficient. I have to actually try at most of my classes. Some things come easily to me and I have pretty decent retention skills but NOTHING is easy enough that I don’t have to study and quite a lot requires a whole bunch of studying (like statistics).
I haven’t been tested since then and that was 18 years ago I have no idea what my IQ is now.
I was pretty smart as a kid; at least I thought so. And that was confirmed by testing.
I’m not so smart as an old guy. And that is confirmed by day to day life.
But still doing OK when compared to my peers.
We are all above average here in Lake Wobegon. Especially if we don’t specify exactly what it is we are measuring. Also, despite their belief otherwise, not all our men are good looking. But they are kind, so we don’t mind. 
FWIW (very little, in other words) my IQ is in approximately the 99.6th percentile. Standardized test scores were always in the 99th percentile growing up. Valedictorian, scholarships, etc. On paper I’m a legitimate genius. In real life, I’m a single mentally-ill mess who dropped out of college with an unchallenging underpaying job and no motivation to improve it.
Proving, once again, that IQ doesn’t mean shit.
I prefer to act on the assumption that I am below-average in every way and a terrible driver too. It helps me get my preparation and planning done.
I was always in the top of my class and used to have an amazing memory.
Age and/or health issues seem to be robbing me of my memory.
I look at my neighbors, here in Dogpatch, & realize I’m above average for the World, & below average for the SDMB.
Let’s see. On the one hand, Lake Wobegon is some odd American thing that I don’t find even slightly amusing. On the other hand, measuring IQ is also a uniquely American pastime.
So being non-American, that puts me above average.
Ha 