16 Specific measures were therefore incorporated into this survey to solve problems of under-numeration, and quality control methods were used to minimise sampling bias.
Although we tried to minimise sampling bias with our methodology, people who attend hospital outpatient clinics are already a self selected group of patients who are attending these clinics for a specific medical reason.
This study aimed to minimise sampling biases and maximise representativeness by using an established community sampling strategy [ 20].
Researchers must overcome methodological and logistical problems, security issues and cultural and language barriers and must minimise sampling biases before they can produce sound research results and more solid conclusions.
To minimise sample bias a number of other procedures were followed.
To minimise sampling bias, assuming an expected 10%% prevalence of awareness on the use of TCAM among respondents within a ±5%% precision, an estimated sample size of 138 was calculated following a formula described in the literature [ 17].
This minimises sampling bias, reduces recall bias and the high ascertainment rate implies that the results will be internally valid.
10 To ensure an even coverage of the UK population and minimise sources of sampling bias, the ONS samples households randomly using the Royal Mail's Postcode Address File.
By approaching consecutive outpatient presentations and systematically sampling the different specialities, the potential for sampling bias was minimised.
