Background: SHOP is a large, randomised, controlled trial designed to evaluate the effect of tailored nutrition education and price discounts on supermarket food purchases. A key objective was to recruit approximately equal numbers of Mâori, Pacific, and non-Mâori, non-Pacific shoppers. This paper describes the recruitment strategies used and evaluates their impact on recruitment of Mâori, Pacific and non-Mâori , non-Pacific trial participants.
Methods: Trial recruitment strategies included: mailed invitations to an electronic register of supermarket customers; in-store targeted recruitment; and community-based recruitment.
Results: Of the 1,103 total trial randomisations for whom ethnicity was known, 247 (22%) were Mâori, 101 (9%) Pacific, and 755 (68%) were non-Mâori, non-Pacific shoppers. Mailed invitations produced the greatest proportion of randomisations (73%, versus 7% in-store, and 20% from community recruitment). However, in-store and community recruitment were essential to boost Mâori and Pacific samples. The cost of mailout (NZ$40 per randomised participant) was considerably less than the cost of community and in-store recruitment (NZ$301 per randomised participant).
Conclusions: Our findings demonstrate considerable challenges and cost in recruiting indigenous and minority ethnic participants into intervention trials. Researchers and funding organisations should allocate more resources to recruitment of indigenous and minority populations compared with recruitment of majority populations. Community recruitment and networks appear to be better ways to recruit these populations than passive strategies like mailouts.