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Last Published April 12, 2026 05:48 PM April 27, 2026 01:30 PM
Primary Outcomes (End Points) 1) The number of toll ring crossings per week per toll tag 2) The percentage difference between the correct price for crossing the toll ring and what the respondent believes. 3) Attitudes towards the toll system in Oslo 1) The number of toll ring crossings per week per toll tag 2) The difference between the correct price for crossing the toll ring and what the respondent believes. 3) Attitudes towards the toll system in Oslo
Primary Outcomes (Explanation) Please see preanalysis plan/Registered Report Please see preanalysis plan
Experimental Design (Public) We will randomly divide our target population, consisting of car drivers, into one treatment group and two control groups. The treatment group will receive two survey invitations and information about the cost of passing the toll road by email every week for 8 weeks. Control group A receives invitations to the baseline and endline survey. Control group B does not receive anything from us. The treatment group consists of approximately 6000 toll tag users, control group A consists of approximately 6000 toll tag users, while control group B consists of the rest of our study population (approximately 108,000 toll tag users). We will randomly divide our target population, consisting of car drivers, into one treatment group and two control groups. The treatment group will receive two survey invitations and information about the cost of passing the toll road by email every week for 8 weeks. Control group A receives invitations to the baseline and endline survey. Control group B does not receive anything from us. The treatment group consists of approximately 6,800 toll tag users, control group A consists of approximately 6,800 toll tag users, while control group B consists of the rest of our study population (approximately 119,000 toll tag users).
Randomization Method Randomization done in office by a computer. Please see more details in preanalysis plan/Registered Report. Randomization done in office by a computer. Please see more details in preanalysis plan.
Planned Number of Observations Approx. 120,000 toll tags for outcome variable 1. 1800 individuals for outcome variable 2 and 3. Approx. 133,000 toll tags for outcome variable 1. 1,800 individuals for outcome variable 2 and 3.
Sample size (or number of clusters) by treatment arms Outcome variable 1: 6000 treatment group, 108,000-114,000 controlgroup Outcome variable 2 and 3: 900 in treatment group, 900 in control group. Outcome variable 1: 6,800 treatment group, 119,000-126,000 control group Outcome variable 2 and 3: 900 in treatment group, 900 in control group.
Power calculation: Minimum Detectable Effect Size for Main Outcomes Please see preanalysis plan/Registered report Please see preanalysis plan
Secondary Outcomes (End Points) Please see preanalysis plan/Registered Report Please see preanalysis plan
Secondary Outcomes (Explanation) Please see preanalysis plan/Registered Report Please see preanalysis plan
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