The Impact of Price Incentives and Behavioral Nudges on Plant-Based Food Consumption: Evidence from a Nationwide Randomized Field Experiment

The study targets receipt-buying and shopping app users and divides them into one control group and seven intervention groups. Among the vast amount of purchasing data, the primary interest of the researchers lies in the purchasing data related to plant-based food (especially plant-based meat). The interventions are implemented as follows:
The control group collects natural purchasing data.

Treatment groups 1 to 3 receive information provision:
- Treatment Group 1 receives information on the environmental impact of PBF (Plant-Based Food)
- Treatment Group 2 receives information on the health impacts of PBF
- Treatment Group 3 receives feedback on their purchase history based on the past six months of PBF purchase data before the intervention

Treatment groups 4 to 7 receive financial incentives for purchasing PBF. In these groups, users who purchase PBF and upload their receipts will be awarded points. Points, equivalent to about 10% of the product price, will be awarded and can be used as cash:
- Treatment Group 4 receives only financial incentives
- Treatment Group 5 receives environmental information plus financial incentives
- Treatment Group 6 receives health information plus financial incentives
- Treatment Group 7 receives feedback on purchase history plus financial incentives

2024-08-13

2024-09-16

Extract the purchase history (amount, quantity, and average unit price) related to the following product data from all purchase records.
Data collection items:
・Plant-Based Foods (PBF) (Soy Meat)
・Fresh Vegetables and Fruits
・Meat: Beef, Pork, Chicken, Processed Meat
・Seafood
・The Other Food Expenditure

The primary objective is to observe the impact of the intervention on PBF purchasing behavior. Additionally, the observation will include the impact on purchasing behavior for other food items (i.e., spillover effects).

One month after the intervention, a survey will be conducted to ask about the consumption status of PBF and meat, impressions in terms of price, health, nutrition, and environmental impact, and attitudes towards switching from meat to PBF. These responses will constitute the secondary outcomes.

This study analyzes the impact of nudges, price incentives, and the combination of both on the purchasing behavior of users of the largest receipt-buying and shopping app in Japan (6 million users). App users upload their purchase receipts daily, with any receipt being bought for 10 JPY. There are active and inactive users, but for this experiment, participants will be randomly selected from among the active users who upload receipts daily. Each group will consist of 400 app users, and since they are unaware of their participation, this experiment is a Natural Field Experiment. As explained above, they will be divided into a control group and seven treatment groups.

For Treatment Groups 1 to 3, a simple questionnaire introducing basic information about PBF (Plant-Based Food) and related nudges will be sent via the app on August 13, the start of the experiment. At this point, attribute information will also be collected. This is the method of information provision. Although it is difficult to determine whether users have viewed the information only through push notifications on the app, completion of the questionnaire will be considered confirmation that they have reviewed the provided information. Subsequently, purchasing data will be collected for approximately five months.

For the groups receiving financial incentives, an icon will be displayed in the app on August 13, indicating that users can earn additional points for purchasing plant-based meat. For users in Treatment groups 5 to 7, additional information on "environment," "health," and "purchase history" respectively is displayed on the app screen. Clicking this icon will be taken as recognition of the additional points offer for PBF purchases. Purchasing data will then be collected by the end of January. The campaign offering additional points for purchasing PBF (Plant-Based Food) will end approximately one month after its introduction. The purpose of this is to observe whether the purchasing habits formed before the incentive period continue after the financial incentives are removed.

In addition, a questionnaire will be administered to both the control and treatment groups approximately one month after the intervention, asking about their thoughts on plant-based meat and their purchasing intentions.

Not available

randomization done by the shopping app developper

individual revel

No

N/A

3,200 individuals

We will set up a control group of 400 people and treatment groups 1 through 7 with 400 people each. Therefore, we will collect purchase data from a total of 3,200 individuals.

We present the results of prior power calculations for each of the outcome variables mentioned above. We set α=0.05 and β=0.2. A prior power analysis (effect size: 0.2, assuming a small effect size, significance level: 0.05, Power (1-β err prob): 0.8) calculated the required sample size to be 394 samples per group. Therefore, for 8 groups, 3200 individuals would need to be secured.