Adverse outcomes of labour in public and private hospitals in Australia

To the Editor: In their national analysis, Robson and colleagues found less favourable outcomes among term singleton babies born in public hospitals than in private hospitals.1 Most health services research is non-randomised, and it is unrealistic to expect studies such as this to be as internally valid as a randomised controlled trial.2 As noted by others,3,4 in the absence of randomisation, it is difficult to untangle the myriad differences between mothers, babies, and the care provided in private and public hospitals (ie, the results might be subject to confounding).