Ritical Appraisal of a Piece of Research

I require a critical appraisal of the following paper.

A national scheme for public access defibrillation in England and Wales: Early results
By Colquhoun M. C., Chamberlain D. A., Newcombe R. G., Harris R., Harris S., Peel K., Davies C. S. and Boyle R.
In Resuscitation (2008) 78, 275 280
Harvard