|
Field
Primary Outcomes (End Points)
|
Before
The primary outcomes will be based on transaction data from the grocery chain that will become available to us after October 1, 2025. We will update this field with more precise information prior to receiving that data, but the focus will certainly be on meat consumption and the impact on CO2-emissions.
|
After
The primary outcomes will be based on transaction data from the grocery chain that will become available to us after October 1, 2025. We will update this field with more precise information prior to receiving that data, but the focus will certainly be on meat consumption and the impact on CO2-emissions.
UPDATE: The primary data source is transaction data from the grocery chain spanning the period January 2025 (or 2024 if possible) until October 2025. This transaction data records all products bought by a customer (who uses either their loyalty card or a registered debit or credit card linked to the loyalty card). The main outcome variables are the product categories included in the survey and for which the treatment group receives information about the carbon footprint and total CO2 emissions.
- Beef
- Pork
- Chicken
- Salmon
- Plant based meat substitutes
- Total CO2 emissions
We will also study in more detail ground meat within the categories above (except salmon), which was a featured product category in the survey and is common in many customers’ baskets.
|
|
Field
Experimental Design (Public)
|
Before
About 75000 members of a Norwegian grocery chain's loyalty program are invited by email to take a survey. We expect about 3000 people to respond and they constitute our sample.
The participants first answer a block of question on demographics, shopping habits and preferences. After that they are randomly assigned to one of three groups:
Control 1 (C1) = No questions about CO2 emissions.
Control 2 (C2) = Questions capturing participants beliefs about CO2 emissions of different meat products.
Treatment (T)= Questions capturing participants beliefs about CO2 emissions of different meat products, AND information about correct CO2 emissions for the same products.
We decided to have two control groups for three reasons. First, it might be that the additional questions asked to the treatment group (T) affects the response rate, which would make it difficult to casually interpret a comparison between T and C1. By including C2 we reduce this risk as that control group answers the same number of questions. Second, it might be that simply asking respondents about their beliefs on CO2-emissions impact purchase behavior, and this we can capture by comparing C2 to C1. Third, by including C2 we can analyze if the treatment effect differ wrt baseline beliefs on CO2 emissions.
IMPORTANT: The main outcome variables are measured using transaction data from the grocery chain covering a period of several months after the survey has been conducted, and the transaction data from the grocery chain will not be accessible to the researchers before October 1, 2025. Hence, there is a clear distinction between the intervention period and the evaluation period. To make a more informed evaluation of the treatment effects we will update this trial after analyzing the survey data BUT before getting access to the transaction data, specifying the primary treatment comparisons to use as well as more details on the primary outcome variables.
|
After
About 75000 members of a Norwegian grocery chain's loyalty program are invited by email to take a survey. We expect about 3000 people to respond and they constitute our sample.
The participants first answer a block of question on demographics, shopping habits and preferences. After that they are randomly assigned to one of three groups:
Control 1 (C1) = No questions about CO2 emissions.
Control 2 (C2) = Questions capturing participants beliefs about CO2 emissions of different meat products.
Treatment (T)= Questions capturing participants beliefs about CO2 emissions of different meat products, AND information about correct CO2 emissions for the same products.
We decided to have two control groups for three reasons. First, it might be that the additional questions asked to the treatment group (T) affects the response rate, which would make it difficult to casually interpret a comparison between T and C1. By including C2 we reduce this risk as that control group answers the same number of questions. Second, it might be that simply asking respondents about their beliefs on CO2-emissions impact purchase behavior, and this we can capture by comparing C2 to C1. Third, by including C2 we can analyze if the treatment effect differ wrt baseline beliefs on CO2 emissions.
IMPORTANT: The main outcome variables are measured using transaction data from the grocery chain covering a period of several months after the survey has been conducted, and the transaction data from the grocery chain will not be accessible to the researchers before October 1, 2025. Hence, there is a clear distinction between the intervention period and the evaluation period. To make a more informed evaluation of the treatment effects we will update this trial after analyzing the survey data BUT before getting access to the transaction data, specifying the primary treatment comparisons to use as well as more details on the primary outcome variables.
UPDATE: In the end, 6,886 customers completed the survey (C1 = 2,471; C2 = 2,202; T = 2,213), meaning we have a larger sample and more statistical power than initially expected. A preliminary analysis of the survey data reveals large misperceptions about CO2 impact, and that our information treatment corrects these misperceptions and affects purchase intentions toward lower-climate-impact products (primarily, reduced beef intentions and increased plant-based intentions). In September 2025, we conducted a follow-up survey (36% response rate) with the objective of testing whether our treatment had a lasting impact on CO2 emission knowledge. Note that we have also updated the field 'Primary outcomes'.
|