In an area with a highly mobile population, there was inevitably
some loss to follow up between the antenatal and postnatal
interviews. This reduced the potential value of the two stage
design in this context. On the other hand, despite the loss to follow
up, the overall response rates were over 65 per cent, a level which
is considered to be more than adequate for surveys of this type. In
particular, they were very much higher than the 33.5 per cent
response rate in the single stage postal survey undertaken in 2007
by Picker Institute Europe as part of the Healthcare Commission's
Review of Maternity Services (Picker Institute, 2007; Healthcare
Commission, 2008). The high response rates at each stage reflected
local women's interest in taking part.