Influences on single-use and reusable cup use: a multidisciplinary mixed-methods approach to designing interventions reducing plastic waste

• Based on reviewer comments, the manuscript has been restructured according to the following:

1) Introduction: frame of the general problem, literature gap, research question, and novelty

1.1) Literature review

2) Method and application

2.1) Design
2.2) Method
2.3) Case study description.

3) Discussion [Due to the nature of the paper (methodology), we have titled the 3^rd subheading you suggest ‘Discussion’ as opposed to ‘Results and Discussion’ as there are no results]

4) Conclusion

• We have made the theory-based nature of the survey more apparent by including Table 2 on page 8-9. Here, we map the domains presented in the COM-B and TDF frameworks, which were introduced in the Introduction, to the proposed survey.
• References to COVID-19 related study disruptions have been removed throughout the manuscript.
• To highlight the importance of impact categories studies when evaluating a product's 'sustainability', on the bottom of page 3 of the manuscript we have included the following: “Life cycle assessments have shown the environmental impacts of different cups to vary depending on the impact categories investigated (11). Examples of different impact categories include stratospheric ozone depletion, resource consumption (e.g., land and water use), ecotoxicity and waste. (12). Evidence suggests that replacing single-use plastic cups for reusable ones can significantly reduce waste generation (though this may increase water consumption) (13).
• The aims are now at the end of the general Introduction on p2, before the literature review.
• Included more references and detail when stating that this study will be a mixed-methods study in the design section.
• Included research on previous efforts made to increase the use of reusable cups: a) Poortinga, W., & Whitaker, L. (2018). Promoting the use of reusable coffee cups through environmental messaging, the provision of alternatives and financial incentives. Sustainability, 10(3), 873; b) Novoradovskaya, E., Mullan, B., Hasking, P., & Uren, H. V. (2021). My cup of tea: Behaviour change intervention to promote use of reusable hot drink cups. Journal of Cleaner Production, 284, 124675.

• As this is an exploratory piece of work, we did not formulate specific hypotheses. However, upon reviewer suggestions, we have been more specific about our study aims. It now reads: 

  To this end, our aims are to present a methodology that identifies: a) current behaviour is with respect to single-use and reusable cup use; b) the various capability, opportunity and motivation related influences on single-use and reusable cup use; c) people’s views on potential intervention strategies to promote reusable cup use

• This is being conducted for multiple linear regression. We have re-run the power analysis using G*Power for a fixed model multiple linear regression analysis.

• We've clarified that convenience sampling will be used.

• To control for whether the participant buys takeaway hot drinks in the first place, we have added the following in the first section of the survey:

  3.2. How often do you purchase hot drinks from cafes/catering outlets?

  3.3. When you buy a hot drink, how often do you get it 'take-away' as opposed to drinking it in the cafe/catering outlet?

  3.4. How often do you purchase hot drinks from UCL cafes/catering outlets?

   3.5. When you buy a hot drink at UCL, how often do you get it 'take-away' as opposed to drinking it in the cafe/catering outlet?

  The revised survey is openly available via OSF (the same link in the manuscript).

Background: An estimated 2.5-5 billion single-use coffee cups are disposed of annually in the UK, most of which consist of paper with a plastic lining. Due to the difficulty of recycling poly-coated material, most of these cups end up incinerated or put in landfills. As drinking (take-away) hot beverages is a behaviour, behaviour change interventions are necessary to reduce the environmental impacts of single-use coffee cup waste. Basing the design of interventions on a theoretical understanding of behaviour increases the transparency of the development process, the likelihood that the desired changes in behaviour will occur and the potential to synthesise findings across studies.

Aim: The present paper presents a methodology for identifying influences on using single-use use and reusable cups as a basis for designing intervention strategies.

Method and application: Two behaviour change frameworks: The Theoretical Domains Framework and the Capability-Opportunity-Motivation-Behaviour model of behaviour, were used to develop an online survey and follow-up interviews. Research findings can inform the selection of intervention strategies using a third framework, the Behaviour Change Wheel. The application of the methodology is illustrated in relation to understanding barriers and enablers to single-use and reusable cup use across the setting of a London university campus.

Conclusions: We have developed a detailed method for identifying behavioural influences relevant to pro-environmental behaviours, together with practical guidance for each step and a worked example. Benefits of this work include it providing guidance on developing study materials and collecting and analysing data. We offer this methodology to the intervention development and implementation community to assist in the application of behaviour change theory to interventions.