The first was regarding infant mortality. After Aaron Sorkin's new show The Newsroom incorrectly reported that the US was 178th in infant mortality (really, you think there are 177 countries you'd rather give birth in?), I went looking for the infant mortality listings across the world. The US does not typically do very well in terms of other industrialized countries.
There are a few interesting reasons for that....we have a much larger population than most of the countries that beat us, and it's spread out over a much larger area. Our care across areas/populations tends to be more uneven, states vary wildly on issues like access, health insurance, prenatal care, etc. Our records however, tend to be meticulous....there is very little doubt that we capture nearly all infant mortality that actually occurs. This combination can put the US at a huge disadvantage in these statistics (10-30% according to the best published studies).
This raises the point of why Cuba tends to beat us. Now, realistically speaking, if you or someone you love had to give birth, would you seriously pick Cuba over the US? Would anybody? And yet they look safer given the data....which is all self reported. I have no problems believing that Singapore outranks us, but I'm skeptical of any country that might have an agenda. Worldwide, there is actually very little consensus on what is a "live birth", and the US tends to use the "any sign of life" definition.
On the other end of the spectrum, I saw this piece recently on gun control. I've covered misleading gun stats before (suicides are often combined with homicides to get "death by gun violence" numbers). One of the interesting facts the article above points out is that internationally, gun deaths are only counted when it's civilian on civilian violence. This is certainly fine in the US...I would think we wouldn't want to count every time the police had to open fire, but in countries with, um, more questionable police tactics, this could cause some skewing (Syria was cited as one such example).
Data is hard enough to pin down when you know the sources have no vested interest in misleading you....international rankings will never be free from such bias.