Skip to content

Social norm nudges in supermarket trolleys to promote vegetable purchases

Social norm nudges in shopping trolleys to promote vegetable purchases: a supermarket experiment in a deprived urban area in the Netherlands

Status
Active, not recruiting
Phases
Unknown
Study type
Interventional
Source
ISRCTN
Registry ID
ISRCTN39440735
Enrollment
244
Registered
2018-09-13
Start date
2018-05-12
Completion date
Unknown
Last updated
2025-10-27

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Vegetable sales Nutritional, Metabolic, Endocrine Vegetable sales

Interventions

The intervention consisted of three green inlays, indicating the space where customers can place their vegetables, each with a different social norm message about vegetable purchases of other customer

Sponsors

Vrije Universiteit Amsterdam
Lead Sponsor

Eligibility

Sex/Gender
All

Inclusion criteria

Inclusion criteria: Supermarket customers in Amsterdam with a shopping trolley and a cash receipt

Exclusion criteria

Exclusion criteria: 1. Not willing to consent to having photograph of cash receipt taken 2. Purchased groceries for more than 12 persons for one day

Design outcomes

Primary

MeasureTime frame
Vegetables purchased (in grams and in items), assessed at the end of each study day over the two-week study period using: 1. Examination of cash receipts 2. Surveys with customers after they had paid for their groceries

Secondary

MeasureTime frame
The following were assessed using oral surveys in the supermarket after customers had paid for their groceries over the two-week study period: 1. Customer characteristics: 1.1. Sex 1.2. Age category 1.3. Highest obtained education 2. Customer grocery behaviour characteristics: 2.1. Number of persons and days for which groceries were purchases 2.2. Use of a shopping list or not 2.3. Place customers purchased vegetables most often 2.4. If customers thought that they purchased less, more or the same amount of vegetables during this shopping trip as they usually would

Countries

Netherlands

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Feb 6, 2026