SPENDING WISELY: INVESTIGATING SURVEY MODE EFFECTS IN DISCRETE CHOICE EXPERIMENT RESPONSES.

"To collect information from patients or the general public researchers often use surveys. In health economics, surveys are used to ask patients or the general public about the kind of National Health Service (NHS) they would like. Typically, these surveys have been sent by post to a random sample of people. Over time the number of people who answer postal surveys has decreased, and recently researchers have turned to the internet to collect information. Internet surveys have several advantages compared to postal surveys: they are cheaper, faster, and can include pictures or videos. But using the internet may change who answers the survey, how they answer the survey questions, and how easy it is for them to provide accurate answers.

Not everyone in the UK has access to and uses the internet: 27% of the UK population do not have access to the internet either through dial-up connections or broadband. People without internet access are, on average, older, poorer and less likely to live in South-East England than those with access. Furthermore, a random sample of UK internet users cannot be asked to complete the survey. First, there is no database of all email addresses. Second, even if there were, sending people unsolicited email (SPAM) is illegal. For these reasons, researchers using the internet to collect information usually pay market research companies for access their 'online panels'. In the UK, these online panels are groups of people who have volunteered to answer surveys online for market research companies in exchange for rewards (money, vouchers, or entry to a prize draw). Market research companies advertise on many websites and search engines to encourage people to volunteer. In 2010 the American Association for Public Opinion Research (AAPOR) advised that researchers should avoid [volunteer] online panels when one of the research objectives is to accurately estimate population values.

Studies have used internet surveys to collect information about patients' or the public's preferences for health care, but few have tested if internet surveys give different results than surveys sent by post or interviews in people's home. The aim of this research project is to concentrate on this knowledge gap and test if different ways of collecting survey information affects the study's results. In particular, are the preferences reported in the internet surveys different from those reported in postal surveys or interviews?

We will compare four ways to collect survey information: internet panel survey, postal survey, postal invitation to complete an internet survey and in-person interviews. We will compare answers to a survey asking the general public about their use of community pharmacies to manage minor illness. We will consider:

- How well respondents to each survey represent the general population
- If the answers people give are different across the different surveys and if this would lead us to different conclusions about the type of community pharmacist service people prefer
- If the quality of people's answers are better for some surveys than others
- By how much the cost of collecting information differs across the different survey types.

The results of this research will help researchers to make decisions about how they collect information from patients or the general public in the future."