When are randomised trials unnecessary? Picking signal from noise

We are glad to see the general agreement with the principles and
examples we set out. However we agree that further work and refinement are
needed if we are to avoid erroneous conclusions about non-randomised
evidence. Further careful examination of examples and the development of
methods will help us tease out which methods apply when. While some may
find the examples simple and plain “common-sense”, they are also important
bridges to more complex areas of evidence. We need to find the harmony
between uncommon sense and common sense (the sense that tells us the world
is flat, but also keeps us alive).

In this regard, the work of Aronson and the development of case-
crossover designs (mentioned by Hocine) are both important and clearly
closely related to the methods we set out. However as Goodman suggests,
though a case or case series or other non-randomised evidence may
sometimes be sufficient, careful Methods are still important if we are to
avoid being caught by Texas sharpshooters and other biases.

Finally like Polowetzky, a number of folk have expressed concerns
about the possible safety of the Mother's Kiss method. To date we have
found no problems reported in the case series, the case reports, and the
experience of folk we have spoken to who have used it, but cleary there is
a need for sufficient cumulative experience. This is analogous to the
safety element of phase IV pharmaco-epidemiological studies after
randomised trials. We plan to study this further, but would appreciate
hearing of anyone's experience, adverse or not, with the Mother's Kiss
method.

Competing interests:
None declared