In discussing the pros and cons of letting babies cry, there is one very important point that must be made first:
If your baby is crying and you feel that you are about to lose control and become upset with your child, leave the room. Leaving baby to cry for a few minutes while you calm yourself will not harm him.
What is controlled crying?
“Controlled crying” is currently used as an umbrella catch-phrase for all sorts of settling techniques, including what can only be called “uncontrolled crying” (the practice of repeatedly leaving a baby to cry himself to sleep).
Actual “controlled crying” or “controlled comforting” requires the parent/carer to wait a prescribed amount of time before entering the room to provide comfort to a crying baby / child.
Does it work?
It can be a useful tool, in some instances, with older children. I find it counter productive with children under two.
Does it harm my baby?
This recent study shows quite clearly the harm that uncontrolled crying can do; an abstract of the research is here:
What this means, in a nutshell, is that babies who are left to cry do stop crying, but they do not stop being stressed.
Do you practice controlled crying?
I neither condone, support, teach nor practice controlled-crying-type methods with small babies.