Tell me about controlled crying

[PickledLily]

I've read a few threads on here that talk about CC being inappropriate, even harmful, for young babies. So I'm hoping someone can clear the waters for me.

Firstly, exactly what is meant by CC, is there an age when it becomes appropriate or not harmful?

Is there research that backs this up ?

And what are the alternatives?

I did CC with dd when she was 7 months. It worked.

I put her to bed, then kept checking on her but would increase the time before going back in.

It took 3 nights to work and now she is a great sleeper

I never ever thought I would leave my child to cry when I was preg and was dead against it for quite a while.
The reality for us was that it was taking a long time to settle ds (measured in hours not minutes) and he still wasn't sleeping thorough at 18 months.
So we did cc, it was horrid but it worked, first time he cried for 45 minutes, next night for about 15 and then he got it and since then he has slept like an angle and even has planned naps for the first time ever.
We did return and reassure recommend by jo frost.
I dont think it's ideal but kids need sleep and so do mums and personally I think our little boy is happier now he's not so over tired.

She's still little, 13weeks. Have had a few comments from relatives about letting her cry, so she knows she can't rule the roost.

Why not before 1 year, what happens developmentally at that point?

This is a good website that has lots of up-to-date research if that's what you're after.

Thanks eaurouge, research is exactly what I'm after