This one falls into the category of "pet peeve", I'm afraid, but it's been on my mind of late.
Here's my complaint: long ago, during the early days of kid #1, someone (birth class instructor? one of he midwives? some blog? I want to say it was something I heard in person rather than read, but I can't be certain) said this about helping babies sleep: "You should put them down when they're ready to fall asleep but still awake, so they learn to fall asleep by themselves. Studies show that babies who are put down while still awake sleep better and wake less than ones who are rocked or nursed to sleep and transferred."
That's not an actual quote, obviously, since I can't even remember if it was a person or a web site that said it. But it stuck with me, because it sounded like a study in which the causal arrow is not in the place or pointing in the direction that the authors want to claim it is.
At the time, we had a baby who was almost never content to be still. At best, she would sit in a chair so long as that chair was vibrating. When she was tired, you had better be walking. Nice soothing glider chair motion? Nope. Not the same. On your feet. Putting her down awake was not going to happen. If she was insufficiently asleep or you flubbed the transfer, she would wind herself up very quickly to a state that required another 10-20 minutes of pacing to calm down from.
We didn't put her down awake because we couldn't. And how did we know we couldn't? Because we had become experts at tracking and interpreting the minute details of her needs and habits, and we had fine tuned, through hundreds of trials, the art of putting her down just as soon as we could, so that we could finally go eat or sleep or get something done, but no sooner.
So my reaction to that description of "studies" was "Of course babies that get put down awake sleep well. That's because they're calm babies! Every one of those parents is putting the kid down as soon as they possibly can."
The problem with this interpretation is that I haven't been able to find the study or studies that are supposed to show this, so I don't know whether any were randomized and controlled. As it was described to me, it sounded like an observational study, but that could have been a mistake.
Anyway, the good news is that baby #2 doesn't require nearly as much motion as the first did. Just occasional mild pacing, but mostly she does well in the glider. The bad news is that there's still no putting her down awake, and in fact she's become harder to transfer and generally worse at sleeping than her big sister ever was. At least as far as we can remember. The mind has a way of letting go of the particularly rough patches (especially when they cause sleep deprivation and mental deterioration).