For this four-arm RCT, an experimental online grocery store will be used. NUSMart Online Grocery Store contains over 3,500 products commonly purchased in local supermarkets (food & beverages only). NUSMart food items are sorted into various categories, such as dairy products, carbonated soft drinks, fresh meats & seafood and snacks. Participants are able to add and remove products to and from their online grocery cart and review their cumulative total cart cost. The web-based grocery store was designed to mirror an actual web-based grocery store in look and feel. All products include pictures of the item, retail prices and product descriptions.
Participants will only be recruited if they are aged 21 years or older, weekly food shoppers, who are the primary grocery shoppers for the household, and are existing registered RedMart customers. Although men are eligible to enroll, we anticipate that the overwhelming majority of subjects will be women.
This will be a crossover study design with all participants exposed once to 4 shopping conditions (1xControl, 1x Arm 2, 1x Arm 3 and 1x Arm 4) in random order. The total study duration for each participant is 4 weeks, with each participant spending 1 week in each shopping condition.
The 4 arms are:
2. Arm 1: A control arm that mirrors a traditional web-grocery store with no HCS or other FOP labels.
3. Arm 2: Similar to Arm 1 except select foods will also be displayed with the new HCS logos, as would currently occur in stores in Singapore.
4. Arm 3: Similar to Arm 2 with additional information displaying calories per serving for all products. These will be displayed next to the price in equal font size.
5. Arm 4: Similar to Arm 2 with additional information graphically displaying Physical Activity Equivalents (PAEs) for all products.
Over the course of the subsequent 4 weeks, participants will log into the NUSMart website once a week and purchase their weekly groceries. Each participant will therefore shop a total of 4 times during the study. This will include 1 shop within each shopping condition (control, Arm 2, Arm 3 and Arm 4). Participants will purchase and receive at least 1 and up to 4 of their grocery orders. This ensures that purchases will be an accurate reflection of their actual shopping experience.
Since there are 4 shopping conditions and the specific weeks that the participant’s shopping trips will be pre-determined for purchase (but unknown to participants), each participant will be randomly assigned at baseline to 1 of 24 groups that vary the sequence of shopping conditions and which shops will result in an actual food delivery.
They will be expected to spend between SGD50 and SGD250. A minimum spend ensures that participants complete a typical weekly grocery order. A maximum spend is to make the study more manageable given foods will need to be reordered and delivered.
The grocery orders that participants purchase will be reordered by Duke-NUS on RedMart, a popular online grocery store in Singapore, and RedMart will deliver the grocery items directly to the participants’ households. The store was created using products currently available on the RedMart website to allow us to repurchase from a single location. At the end of the study participants who have completed all 4 shops as instructed will receive a RedMart e-Voucher worth $75 payment that can be redeemed against any products on RedMart.