Robin on Liddcombe

Here are some additional-to-my comments by Robin Lickley on the Lidcombe RCT (Random Control Trial):

(1) If you (i.e., 'one') accept that the Lidcombe RCT shows a treatment effect, then you may conclude that some (not necessarily all all) of the Lidcombe treatment is effective. But you can't conclude that this means that Lidcombe Prog is better than other therapies, because there is no similar test of other therapies. As the Lidcombe BMJ paper suggests, the most that can be concluded is that Lidcombe is better than nothing.
I think this is just restating this risks in your point 3.

(2) An additional consideration that is overlooked just about everywhere concerns what/who is being treated and assessed.
Almost all discussion of the efficacy of this programme makes the assumption that it treats what it says (or implies) it's treating: that is, it's treating the disorder that would otherwise turn into persistent stuttering.
However, obviously, we can be reasonably sure that a lot of the kids in the treatment arm would have recovered spontaneously - they're the ones with transient stuttering (TS). It is not unreasonable to suggest that these TS kids could also benefit from treatment and recover faster than they would otherwise.

If it is the case that children with transient stuttering can benefit from therapy, then if you were able to identify a group of 54 kids with transient stuttering, divide them into 2 groups and treat one group with the Lidcombe programme, while leaving the others alone, you might just get very similar results as those reported in the BMJ.

In the most pessimistic view, it could be that transient stuttering and persistent developmental stuttering have different etiologies and require different interventions and that the various therapies for children who stutter are actually only effective in speeding recovery of those with transient stuttering and not effective at all in preventing the continuation of persistent developmental stuttering.

I can almost hear you thinking 'we need brain imaging studies on kids in order to differentiate', but behavioral studies can also be revealing.
Cheers,
Robin