ObesityNCT02914821
Do Taxes Reduce the Purchasing of Soda?
A study testing Simulated tax via 3 cent per ounce price increase in people with Obesity and Diabetes, run by Harvard University.
Trial summary
The study will take place at a cafe managed by university dining services and is located in a university building adjacent to the psychology building. The cafe sells sugar-sweetened beverages and a variety of diet drinks. Read more about this study
- Who is it for?
- Any ageHealthy volunteers can take part
- What is being tested?
- Simulated tax via 3 cent per ounce price increase
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 50 participants
- Where
- No sites listed yet
- Study dates
- 1 Sep 2016to 1 Jan 2018
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- All sexes
- Healthy volunteers accepted
- Child, Adult, Older adult
Who may be able to join
- All patrons who purchase a beverage at our study site (retail cafe) during the intervention are eligible for inclusion. The cafe is open to the public, though it primarily serves staff, patients and guests of the research labs in the building.
Who cannot join
- There are no exclusion criteria.
About this study
The study will take place at a cafe managed by university dining services and is located in a university building adjacent to the psychology building. The cafe sells sugar-sweetened beverages and a variety of diet drinks. The campus dining services and the manager of the cafe have given investigators permission to "tax" their sugar sweetened beverages and will provide their sales data for a 12 week period.
The investigators will introduce four arms to the experiment. One arm will be baseline data where business 'as usual' will be conducted and no price increases will be implemented on SSBs. In the general tax condition the investigators will introduce a 3 cent/ounce tax on the five SSB flavors the café offers. In the Pre-K tax condition the investigators will institute a 3 cent/ounce tax but will label the tax as proceeds going to Pre-K education. This is designed after the Philadelphia tax that was recently passed where funds were earmarked to benefit childhood education. In the childhood healthy eating program condition the investigators will institute a 3 cent/ounce tax but will label the tax as proceeds going toward childhood healthy eating programs. In all tax conditions the firm will keep the proceeds, but the research team will make a donation to a Pre-K education non-profit and a childhood healthy eating non-profit of the amount generated by the tax during the study period.
Read more
Each experimental arm will run for 3 weeks total (for a total study period of 12 weeks). The conditions will alternate by week (i.e., week 1: business as usual; week 2: general tax; week 3: pre-K tax; week 4: childhood healthy eating tax; week 5: business as usual, etc). A research assistant will visit the café each week to make any necessary changes to signs that will label the drinks.
The investigators will change the signage of the drinks in the cooler during the study period. For the baseline period there will be no changes to the signs made. Currently all beverages are labeled with their name and cost (e.g., Pepsi, $1.89). In the tax conditions the investigators will change the price of the drink (3 cents/ounce) and add a line notifying consumers of the soda 'surcharge' (note "surcharge" will be used in the study because no tax was actually passed by the local government). An example of this sign would be 'Pepsi, $2.29, includes 40 cent sugary drink surcharge.' In the Pre-K tax condition an added line will say, "Pepsi, $2.29, includes a 40 cent sugar sweetened beverage surcharge. Proceeds benefit Pre-K education." In the childhood healthy eating programs condition the text will say, "Pepsi, $2.29, includes a 40 cent sugary drink surcharge. Proceeds benefit Childhood Healthy Eating programs."
Read the detailed description
Diet-related diseases, such as diabetes and obesity, have become pervasive global health challenges, so much so that they are being called epidemics. The problem is particularly acute in the United States where two-thirds of adults and one-third of children are overweight or obese. A key contributor to increased dietary intake is the increased consumption of sugar-sweetened beverages.
Sugar-sweetened beverages (SSBs), also known as soft drinks, are beverages that are sweetened with sugar, high fructose corn syrup, or any other caloric sweetener; this excludes noncaloric (diet) drinks. The average American consumes approximately 47 gallons of SSBs per year. Americans consume about 278 calories more each day than they did 30 years ago and nearly half of this increase is attributable to increased consumption of SSBs. The consumption of SSBs has been cited as a key contributor to obesity and has been linked to other negative health problems, such as diabetes, heart disease, and dental cavities. Therefore, the increase in SSB consumption and the concurrent increase in diet-related diseases pose significant direct and indirect costs to society.
In response to these problems, health experts, laypeople and legislators alike advocate policies to reduce the consumption of SSBs. Several municipalities and states have proposed policies such as taxes, warning labels, and calorie labeling and a few have passed such policies. For example, Berkeley, CA recently adopted a SSB excise tax which charges an additional cent for each ounce of SSB sold. In June 2016, Philadelphia passed a 1.5 cent per ounce tax on sugary drinks and diet sodas.
The investigators believe it is critical to further test the effectiveness of taxes in the field. In this study, the investigators conduct a field experiment that tests different framing of taxes, namely whether the money is earmarked for a particular cause.
- Being tested
- Simulated tax via 3 cent per ounce price increase
- Keywords
- consumption, decision making, policy, sweetened beverages, taxes, Diet, Food, and Nutrition
- Medical subject headings
- Obesity, Diabetes Mellitus
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Simulated tax via 3 cent per ounce price increaseBehavioural
For each of the 3 experimental conditions, investigators will increase the price of sugar-sweetened beverages by 3 cents per ounce. This price increase will be reflected in the price tag and described as a surcharge. In two of the arms (Pre-K and Childhood Healthy Eating), the beneficiary of the surcharge will be named.
| Study group | Role | What they receive |
|---|---|---|
| Business as Usual (No "Tax") | No intervention | Baseline data where business 'as usual' will be conducted and no price increases will be implemented on SSBs. |
| General "Tax" (without named beneficiary) | Experimental | In the general tax condition investigators will introduce a 3 cent/ounce tax on the five SSB flavors the café offers. An example of this sign would be 'Pepsi, $2.29, includes 60 cent sugary drink surcharge.' Receives: Behavioral: Simulated tax via 3 cent per ounce price increase |
| Pre-K "Tax" | Experimental | In the Pre-K tax condition investigators will institute a 3 cent/ounce tax but will label the tax as proceeds going to Pre-K education. An example of this sign is, "Pepsi, $2.29, includes a 60 cent sugary drink surcharge to fund Pre-K education." Receives: Behavioral: Simulated tax via 3 cent per ounce price increase |
| Childhood Healthy Eating "Tax" | Experimental | In the Childhood Healthy Eating tax condition investigators will institute a 3 cent/ounce tax but will label the tax as proceeds going to Pre-K education. An example of this sign is, "Pepsi, $2.29, includes a 60 cent sugary drink surcharge to fund Childhood Healthy Eating education." Receives: Behavioral: Simulated tax via 3 cent per ounce price increase |
What is being measured
The primary outcome is the main question the study is designed to answer.
Sugar-Sweetened Beverages Sold by Universal Product Code (UPC)
Using the Universal Product Code (UPC) obtained in sales data, we will sum the total number of sugar sweetened beverages sold in each condition and can calculate this as a share of total beverages sold.
Measured: 3-week condition blocks
Secondary outcomes (3)
Average Number of Beverage Calories Purchased Per Customer
Using the UPCs and nutrition labels, we will calculate the average number of calories purchased that come from beverages.
Measured: 3-week condition blocks
Unsweetened Beverages Sold by Universal Product Code (UPC)
Using the Universal Product Code (UPC) obtained in sales data, we will sum the total number of unsweetened beverages sold in each condition and can calculate this as a share of total beverages sold.
Measured: 3-week condition blocks
Changes in types of beverages purchased
We will examine any changes in the types of beverages purchased during each condition, using the Universal Product Code (UPC) for bottled beverages. For example, if sugar-sweetened beverages sales decrease, do purchases of water increase?
Measured: 3 week condition blocks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Sep 2016 (estimated)
- Study start1 Sep 2016
- Primary completion1 Jan 2018
- Study completion1 Jan 2018
Why it stopped: Harvard University dining workers went on strike, we hope to relaunch in Fall 2017.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ObesityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 50 participants (actual)
Sponsor and investigators
- Lead sponsor
- Harvard University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Leslie John, Harvard University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02914821
- Sponsor's protocol ID
- IRB16-1285
- Status last verified
- Oct 2018
- First submitted
- 3 Sep 2016
- Last updated
- 4 Oct 2018
- Results posted
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 4 Oct 2018. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Do Taxes Reduce the Purchasing of Soda?
- ClinicalTrials.gov ID
- NCT02914821
- Acronym / sponsor ID
- IRB16-1285
- Keywords
- consumption, decision making, policy, sweetened beverages, taxes, Diet, Food, and Nutrition
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Harvard University dining workers went on strike, we hope to relaunch in Fall 2017.
- Enrolment
- 50 participants (actual)
- Lead sponsor
- Harvard UniversityUniversity, hospital or other
- Study start
- 1 Sep 2016 (actual)
- Primary completion
- 1 Jan 2018 (actual)
- Study completion
- 1 Jan 2018 (actual)
- First posted
- 26 Sep 2016 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The study will take place at a cafe managed by university dining services and is located in a university building adjacent to the psychology building. The cafe sells sugar-sweetened beverages and a variety of diet drinks. The campus dining services and the manager of the cafe have given investigators permission to "tax" their sugar sweetened beverages and will provide their sales data for a 12 week period.
The investigators will introduce four arms to the experiment. One arm will be baseline data where business 'as usual' will be conducted and no price increases will be implemented on SSBs. In the general tax condition the investigators will introduce a 3 cent/ounce tax on the five SSB flavors the café offers. In the Pre-K tax condition the investigators will institute a 3 cent/ounce tax but will label the tax as proceeds going to Pre-K education. This is designed after the Philadelphia tax that was recently passed where funds were earmarked to benefit childhood education. In the childhood healthy eating program condition the investigators will institute a 3 cent/ounce tax but will label the tax as proceeds going toward childhood healthy eating programs. In all tax conditions the firm will keep the proceeds, but the research team will make a donation to a Pre-K education non-profit and a childhood healthy eating non-profit of the amount generated by the tax during the study period.
Each experimental arm will run for 3 weeks total (for a total study period of 12 weeks). The conditions will alternate by week (i.e., week 1: business as usual; week 2: general tax; week 3: pre-K tax; week 4: childhood healthy eating tax; week 5: business as usual, etc). A research assistant will visit the café each week to make any necessary changes to signs that will label the drinks.
The investigators will change the signage of the drinks in the cooler during the study period. For the baseline period there will be no changes to the signs made. Currently all beverages are labeled with their name and cost (e.g., Pepsi, $1.89). In the tax conditions the investigators will change the price of the drink (3 cents/ounce) and add a line notifying consumers of the soda 'surcharge' (note "surcharge" will be used in the study because no tax was actually passed by the local government). An example of this sign would be 'Pepsi, $2.29, includes 40 cent sugary drink surcharge.' In the Pre-K tax condition an added line will say, "Pepsi, $2.29, includes a 40 cent sugar sweetened beverage surcharge. Proceeds benefit Pre-K education." In the childhood healthy eating programs condition the text will say, "Pepsi, $2.29, includes a 40 cent sugary drink surcharge. Proceeds benefit Childhood Healthy Eating programs."
Detailed description
Diet-related diseases, such as diabetes and obesity, have become pervasive global health challenges, so much so that they are being called epidemics. The problem is particularly acute in the United States where two-thirds of adults and one-third of children are overweight or obese. A key contributor to increased dietary intake is the increased consumption of sugar-sweetened beverages.
Sugar-sweetened beverages (SSBs), also known as soft drinks, are beverages that are sweetened with sugar, high fructose corn syrup, or any other caloric sweetener; this excludes noncaloric (diet) drinks. The average American consumes approximately 47 gallons of SSBs per year. Americans consume about 278 calories more each day than they did 30 years ago and nearly half of this increase is attributable to increased consumption of SSBs. The consumption of SSBs has been cited as a key contributor to obesity and has been linked to other negative health problems, such as diabetes, heart disease, and dental cavities. Therefore, the increase in SSB consumption and the concurrent increase in diet-related diseases pose significant direct and indirect costs to society.
In response to these problems, health experts, laypeople and legislators alike advocate policies to reduce the consumption of SSBs. Several municipalities and states have proposed policies such as taxes, warning labels, and calorie labeling and a few have passed such policies. For example, Berkeley, CA recently adopted a SSB excise tax which charges an additional cent for each ounce of SSB sold. In June 2016, Philadelphia passed a 1.5 cent per ounce tax on sugary drinks and diet sodas.
The investigators believe it is critical to further test the effectiveness of taxes in the field. In this study, the investigators conduct a field experiment that tests different framing of taxes, namely whether the money is earmarked for a particular cause.
Study design
- Primary purpose
- Other
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Business as Usual (No "Tax") | No intervention | –Baseline data where business 'as usual' will be conducted and no price increases will be implemented on SSBs. |
| General "Tax" (without named beneficiary) | Experimental | Behavioral: Simulated tax via 3 cent per ounce price increaseIn the general tax condition investigators will introduce a 3 cent/ounce tax on the five SSB flavors the café offers. An example of this sign would be 'Pepsi, $2.29, includes 60 cent sugary drink surcharge.' |
| Pre-K "Tax" | Experimental | Behavioral: Simulated tax via 3 cent per ounce price increaseIn the Pre-K tax condition investigators will institute a 3 cent/ounce tax but will label the tax as proceeds going to Pre-K education. An example of this sign is, "Pepsi, $2.29, includes a 60 cent sugary drink surcharge to fund Pre-K education." |
| Childhood Healthy Eating "Tax" | Experimental | Behavioral: Simulated tax via 3 cent per ounce price increaseIn the Childhood Healthy Eating tax condition investigators will institute a 3 cent/ounce tax but will label the tax as proceeds going to Pre-K education. An example of this sign is, "Pepsi, $2.29, includes a 60 cent sugary drink surcharge to fund Childhood Healthy Eating education." |
Who may qualify
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (1 listed)
- All patrons who purchase a beverage at our study site (retail cafe) during the intervention are eligible for inclusion. The cafe is open to the public, though it primarily serves staff, patients and guests of the research labs in the building.
Key exclusion criteria (1 listed)
- There are no exclusion criteria.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Simulated tax via 3 cent per ounce price increaseFor each of the 3 experimental conditions, investigators will increase the price of sugar-sweetened beverages by 3 cents per ounce. This price increase will be reflected in the price tag and described as a surcharge. In two of the arms (Pre-K and Childhood Healthy Eating), the beneficiary of the surcharge will be named. | Behavioural | Childhood Healthy Eating "Tax", General "Tax" (without named beneficiary), Pre-K "Tax" |
Primary outcome
Sugar-Sweetened Beverages Sold by Universal Product Code (UPC)
Time frame: 3-week condition blocks
Using the Universal Product Code (UPC) obtained in sales data, we will sum the total number of sugar sweetened beverages sold in each condition and can calculate this as a share of total beverages sold.
3 secondary outcomes
Average Number of Beverage Calories Purchased Per Customer
Time frame: 3-week condition blocks
Unsweetened Beverages Sold by Universal Product Code (UPC)
Time frame: 3-week condition blocks
Changes in types of beverages purchased
Time frame: 3 week condition blocks
Results and safety
The study was stopped early (reason given: Harvard University dining workers went on strike, we hope to relaunch in Fall 2017.). Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Oct 2018.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
A study testing Simulated tax via 3 cent per ounce price increase in people with Obesity and Diabetes, run by Harvard University.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 4 Oct 2018. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study was stopped early (reason given: Harvard University dining workers went on strike, we hope to relaunch in Fall 2017.). Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Sugar-Sweetened Beverages Sold by Universal Product Code (UPC) (time frame: 3-week condition blocks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Oct 2018.