2.5 Bias
As the survey was distributed online via a UK-based charity, there is a
selection bias towards the members of the charity, members with internet
access and UK residents. In addition, individuals with more significant
olfactory dysfunction may be more likely to respond. There is a risk of
response bias as participants tend to agree or provide positive answers
in, e.g. in rating scales and yes/no questions. We aimed to mitigate
this issue by incorporating free text boxes to allow participants to be
more nuanced.