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Diet Improvement Through Normative Experimentation (DINE)

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Duke University

Status

Completed

Conditions

Diet Quality

Treatments

Behavioral: Financial Incentives leveraging on loss aversion
Behavioral: Norm-based messaging and peer comparison features

Study type

Interventional

Funder types

Other

Identifiers

NCT05070442
NIHA-2018-002 (Study 2)

Details and patient eligibility

About

This study aims to use a three-arm randomized control trial (RCT) implemented in a fully functional experimental online grocery store, to explore the effects of two low-cost information and incentive-based strategies. These strategies comprise of injunctive norm-based messaging and the use of financial incentive leveraging on loss aversion to encourage the purchase of healthy foods. The investigators have set up a store wherein products may be purchased by participants and subsequently delivered to homes in some of the conditions. This increases the external validity of these interventions and enables investigators to establish greater confidence in their generalizability.

Full description

The Asia-Pacific is faced with an epidemic of rising rates of chronic disease. Poor diet quality is a demonstrated risk factor for non-communicable diseases. Excess intake of calories, saturated fat and sodium increases the risk of obesity, heart disease, diabetes, and other chronic conditions.

Behavioral economics has emerged as a promising strategy to increase the effectiveness of interventions aimed to address risk factors for non-communicable diseases (NCDs). Yet, there is a gap in knowledge concerning how norm-based messaging and peer influence interventions can be implemented to improve diet quality.

Using a three-arm randomized trial with a 3x3 crossover design, investigators aim to determine whether norm-based messaging and peer comparisons, with or without financial incentives, improve diet quality.

Each participant will be exposed to all of the following intervention arms in random order:

Arm 1: Control arm. Participants will experience an unmodified version of NUSMart which replicates the traditional shopping experience of online grocery stores.

Arm 2: Participants will experience a modified version of NUSMart with norm-based messaging and peer comparison features enabled. Nutri-Score labels will be enabled and displayed on all products within the store. A floating side panel will provide a visual indicator of the participants' average weighted Nutri-Score.

Arm 3: Same as Arm 2, except participants are notified of an additional $5 reward towards participation reimbursement. However, this additional $5 will be forfeited if the basket average weighted Nutri-Score falls below the average of participants' peers'. (Financial incentive leveraging on loss aversion).

Investigators hypothesize the following:

Primary hypothesis: Diet quality, as measured by mean Nutri-Score weighted by number of servings of all basket items, will be greatest when exposed to the intervention with norm-based messaging with incentive (Arm 3), followed by the intervention with norm-based messaging without the incentive (Arm 2), followed by Control (Arm 1).

Investigators will test this hypothesis in total, and separately for foods and beverages given Singapore's focus on reducing intake of sugar-sweetened beverages.

Enrollment

248 patients

Sex

All

Ages

21+ years old

Volunteers

Accepts Healthy Volunteers

Inclusion criteria

  • Singapore resident
  • Age 21 and above
  • Must be the primary weekly grocery shopper in their household

Exclusion criteria

  • Non-Singapore resident
  • Non-primary grocery shopper in their household
  • Less than 21 years old

Trial design

Primary purpose

Health Services Research

Allocation

Randomized

Interventional model

Crossover Assignment

Masking

Triple Blind

248 participants in 3 patient groups

Control Arm (Arm 1)
No Intervention group
Description:
Participants will experience an unmodified version of NUSMart which replicates the traditional shopping experience of online grocery stores.
Norms Arm (Arm 2)
Experimental group
Description:
Participants will experience a modified version of NUSMart with norm-based messaging and peer comparison features enabled. Nutri-Score labels will be enabled and displayed on all products within the store. A floating side panel will provide a visual indicator of the participants' average weighted Nutri-Score.
Treatment:
Behavioral: Norm-based messaging and peer comparison features
Norms and Incentive Arm (Arm 3)
Experimental group
Description:
Same as Arm 2, except participants are notified that they have been awarded an additional $5 towards their participation reimbursement. However, this additional $5 will be forfeited if their basket average weighted Nutri-Score falls below the average of their peers'. (Financial incentive leveraging on loss aversion).
Treatment:
Behavioral: Norm-based messaging and peer comparison features
Behavioral: Financial Incentives leveraging on loss aversion

Trial contacts and locations

1

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Data sourced from clinicaltrials.gov

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