Upon arriving at the BLUE lab, all participants will be asked to fill out an initial questionnaire which will include questions related to demographics, socio-economic background, education, employment status, as well as various questions related to their prior knowledge regarding health, nutrition and their own health status. Participants will also be asked to complete a short food frequency questionnaire (based on the National Cancer Institute's Dietary Screener Questionnaire) in order to obtain a measure of their typical eating habits.
Following this initial stage, we will then move on to the actual interventions.
Subjects will be randomly-assigned to one of six (6) groups upon registration:
1) Information Control/Low Priority
2) Information Control/High Priority
3) Generic Information/Low Priority
4) Generic Information/High Priority
5) Tailored Information/Low Priority
6) Tailored Information/High Priority
The first intervention in our study is related to the provision of different types of health information our subjects. In particular, we are interested in understanding the impact of the provision of tailored versus generic health information on people's food choices. We shall have a control group (Information Control) who will be provided with non-health related news stories and articles to read, taken from local and international media outlets.
The tailored information treatment group will be provided with personalised health information via an adapted version of a computer-based assessment tool called `Your Disease Risk' (YDR), which was developed by Washington University in St. Louis and Harvard University. The algorithms developed for this tool are used to measure the risk of ever contracting a particular disease, relative to the average person of the same age and gender. We have adapted the algorithm for the Scottish population using data from the Scottish Health Survey. These calculations are done on the basis of a series of questions that respondents are asked to fill in, related to their medical history, their parents' medical history, dietary habits (e.g. consumption of fruit and vegetables per day) and lifestyle choices (e.g. smoking, exercise, average daily alcohol consumption). Once these questions are answered, the YDR tool provides a scale showing the respondent's relative risk of contracting a particular disease, which ranges from `Low' to `High' (e.g. `Very Much Below Average', `Average', `Much Above Average', etc.). The system also supplies tailored recommendations to respondents which would help them to lower their risk (e.g. `Eat more unsaturated fats', `Stop smoking'.). For the purposes of this study, we shall be focussing solely on two diseases, namely heart disease and diabetes. Note that the questions required as inputs for the YDR tool are already included in the initial questionnaire described earlier, and hence will be answered by all participants. However, the Tailored Information group will be the only subjects to receive the YDR risk and recommendations (other groups will not be aware of this treatment).
The generic information treatment group will answer the same series of questions that respondents are asked to fill in for the tailored information treatment. At the end of these series of questions individuals will be given the average risk of developing cardiovascular and diabetes. For example, they will be told 1.5 people out of 100 will develop heart disease in Scotland within 10 years. This risk will be calculated using the same data as the tailored treatment but just for the entire Scottish population and will not be specific to the individual. They will then be given a comprehensive list of lifestyle changes that can be done to reduce the risk. The design is set up to ensure maximum comparability across treatments as this will allow us to assess the marginal impact of tailored health information relative to generic information.
The second intervention in our study is related to the time available for each participant to make their food choices. The idea behind this treatment is that people have limited cognitive resources that must be allocated across various competing concerns, meaning that matters related to nutrition and health may not be high on an individual's list of priorities. This is particularly true in the case of most foods high in fat and sugar since most unhealthy foods yield immediate benefits in terms of taste or gratification while healthier foods are typically associated with more long-term benefits that may at present seem remote or even unclear. The lack of health prioritisation may be more acute for people from a low income background since various studies (e.g. Mani et al, 2013) have shown that poverty-related concerns occupy a large portion of a low-income person's mental resources, leaving less room for focussing on other matters. Therefore in this study we are explicitly trying to test this idea by introducing exogenous variation in the amount of time available for subjects to make their dietary choices.
At the start of this intervention, all participants will be allocated a budget of £30 in order to spend on food and drink from a specially-designed choice tool that appears similar to an online supermarket developed specifically for this study using VBA. The choice tool contains a total of 100 food and drink items, and an equal mixture of both healthy and unhealthy items across various grocery categories like fruit and vegetables, meat, fish, confectionery, chilled meals and drinks. Apart from capturing the participants' food choices in terms of which items were actually selected, the system has been designed to calculate the nutritional value of each basket along several key nutrients, namely carbohydrates, saturated fats, salt content, sugar content, fibre and protein. These will serve as our key outcome variables when analysing the data. All prices used in the online supermarket reflect current market prices at the leading high street supermarkets in the UK, in order to make the food selection task more realistic. Subjects will be allowed to spend their budget on any of the items listed in the online supermarket, just as long as they do not exceed the £30 limit. The experimental variation is related to the time available to select their food and drink items. The High Priority group will be given a longer time period to make their choices (and will be required to stay for the entire duration), while the Low Priority group will be given a shorter time period. Both time periods will be pre-tested in BLUE before the start of the experiment. At the end of each session, 1 subject per session will be picked at random and his/her food basket will be delivered to his/her home address within one week.
Post-Treatment and Follow-up
At the end of the study, all participants will be asked to fill in a short questionnaire, which is primarily designed to elicit three key facts:
Whether the participants updated their beliefs regarding their own health status following the information treatment;
Whether the participants believe that the information provided was credible/trustworthy or not;
Whether the choice tool was easy to use and comparable to their typical supermarket shopping experience.
This concludes the main session of our study. In order to gauge the long-term impact of the health information intervention, we plan on running a follow-up session 3 months later (in September 2016). In this session, participants will be asked to complete a short questionnaire to elicit their updated beliefs regarding their health status and whether they have undertaken any dietary changes (particularly for those who received tailored health information), the food frequency questionnaire, a 24-hour dietary recall (using the INTAKE24 software developed specifically for the UK by Newcastle University), and will once again be allocated a £30 budget to spend using our choice tool. In this instance there will be no time restrictions on their food choices - all participants will have a maximum of 30 minutes to make their choices and will not be required to stay for the entire time period. We will record the amount of time they stay in the laboratory and spend on the task.