JMIR Publications

ABSTRACT

Background:

Virtual supermarkets offer a practical and affordable means to test the efficacy of different pricing and nudging strategies before they are implemented in real-world settings. Despite the advantages of using virtual supermarkets, conducting studies an online settings have the disadvantage of participants being more difficult to recruit and retain.

Objective:

To describe the costs, feasibility and results of several recruitment strategies and participants’ appreciation and usability of the Supreme Nudge Virtual Supermarket (SN VirtuMart).

Methods:

This cross sectional study used data from a randomized controlled trial where 455 Dutch adults with low or high educational level were asked to conduct five shops within a three-dimensional virtual supermarket. The SN VirtuMart, developed in 2018, resembled a Dutch supermarket containing almost 1200 unique food and beverage products. Participants were asked to conduct five shops in the SN VirtuMart and complete questionnaires on demographics, food purchasing habits and feedback on the SN VirtuMart. A log to track the costs of the different recruitment strategies was kept by the study team. Outcome measures included the cost of recruitment strategies, recruitment and attrition rates, and appreciation and usability of the SN VirtuMart.

Results:

In total, 346 participants completed the study (completion rate: 74%). The median age was 31.0 (IQR: 25.0) and 45.4% were highly educated. N=235 (52%) were recruited via social media campaigns, N=131 (29%) via home-delivered flyers, N=38 (8%) via flyers received from the study team and N=46 (10%) via word-of-mouth. Out of all paid recruitment strategies, social media campaigns were the cheapest and flyers received from the study team was the most expensive recruitment strategy. Participant demographics varied by recruitment strategy. Most participants found the SN VirtuMart easy to use (90.8%) and found that their purchases resembled those made in real life (78.2%).

Conclusions:

Using different recruitment strategies resulted in an efficient recruitment of a representative study sample and retention of participants was relatively high. The SN VirtuMart was generally appreciated by the participants. It thus seems feasible to use the SN VirtuMart to test the efficacy of different pricing and nudging strategies before they are implemented in real-world settings. Clinical Trial: The trial conducted in the SN VirtuMart was registered in the Dutch trial registry (www.trialregister.nl) under report number NTR7293.