Alternatives to single-use plastics: Appendix B Search Protocol

Review of evidence base for alternatives to single-use plastics in food packaging and production

Evidence review protocol overview

Research aims

The core focus of this research will be to search, gather, review, synthesise and report literature which provides evidence on the growing market of alternatives to single-use plastics within the food industry. More specifically, literature that provides insight into the types of alternatives and their current use, emerging trends in innovation, consumer preferences and the changing policy environment for the FSA will be key. Through the process, the quality and quantity of the evidence will be considered, identifying gaps where they exist.

Priority research questions

Protocol for searching, screening and reviewing the literature

Stage 1: Database searches

We will be reviewing relevant literature from two sources. The first source is academic literature which has been published in scientific journals. The second is grey literature which originates from the UK government and its public agencies, international public agencies, non-governmental organisations, market reports and patents. Rachael Posaner (University of Birmingham, Knowledge, and Evidence Services (KES)) will conduct the search for published/academic literature via the University of Birmingham Library Services based on agreed search terms, whilst RSM will conduct the search for grey literature and manage the wider call for evidence. We will use the PRESS checklist ^{(footnote 1)} to structure our search strategy and fully optimise the time available for the search.

Our advisor Dr Samuel Short will be asked to contribute any key sources, including those not yet published, available to them given their academic knowledge and network. RSM will also issue a call for evidence and ask the FSA expert panel, and our advisor to disseminate this call for evidence.

We propose the following search criteria and databases. Parameters may need to be refined depending on the scarcity of available and relevant sources.

Search terms and inclusion criteria

Stage 2: Screening of titles and abstracts

Using our various sources of literature, we will review a longlist of a maximum 600 titles of published and unpublished studies, articles and reports (‘grey literature’) pertaining to the research questions on single-use plastic alternatives as specified above. 

The table below sets out the first level inclusion/ exclusion criteria which we will apply to each title. We anticipate excluding 25% to 50% of titles at this point either because they are not of central relevance to single-use plastic alternatives, or they are duplicate studies in our sample.

We will then review around 300 abstracts and executive summaries at the second stage of screening, having already excluded irrelevant titles and duplicates. The second level criteria are listed below and relate to the detailed research questions. These may need to be refined depending on the number of studies retrieved. Abstracts which do not meet any second level inclusion criteria will be discarded and the remaining abstracts will form the shortlist of relevant literature for further screening and quality assessment.

Stage 3: Quality assessment of full texts

After removing irrelevant abstracts, we expect to shortlist about 60 full texts. They will be examined and screened to identify the final list of the most relevant, informative and useful studies to undergo full review. The selection will be based on tighter inclusion criteria, including quality measures i.e. the extent to which methodologies/ evidence bases are robust following DEFRA guidance ^{(footnote 2)} using the following steps:
 
a)    Score the relevance of the evidence for each research theme on a 3-point scale, (from 1=low to 3=high), considering:
•    To what extent does this text help to provide an evidence-based answer to the research question/s that come under this theme?
b)    Score the robustness of the evidence on a 3-point scale (from 1=low to 3=high) where the following rating system would apply: 

c)    Combine the two scores from a) and b) into one final measure of quality, i.e. scored from 1 (1*1) up to 9 (3*3) and coded to result in a red-amber-green rating.
d)    Present the process and results clearly to ensure transparency and replicability. 

Throughout the search process, a log will be kept on a spreadsheet which will eventually be developed into the full literature review log in the next stage of the search protocol.

Stage 4: Full review and data extraction

We will complete a full review of a maximum of 60 papers or reports, and extract information from the review literature into a spreadsheet which can be filtered for each research theme. The suggested headings for the spreadsheet are below. If after reviewing all full texts significant gaps in the literature remain, it may be required that we conduct a purposive second round search to gather new information to conduct a complete STEEPLE analysis.

To keep our approach structured, we will follow the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) reporting items ^{(footnote 3)} to allow for a transparent, encompassing and comparable collection of article records included in our final review list.

Headings for the full literature review log:

• document title
• author(s)
• date of publication
• organisation/owner
• study type
• aims 
• methodology
• summary of findings
• strengths
• limitations
• evidence gaps
• quality appraisal - relevance
• quality appraisal - robustness
• research questions

Quality appraisals will be completed concurrently with the extraction process. We will ensure that our work meets quality ratings according to AMSTAR (A Measurement Tool to Assess Systematic Reviews) ^{(footnote 4)}.

Findings across the evidence base will be synthesised following ESRC guidance on conducting narrative synthesis ^{(footnote 5)}. The synthesis will be grouped by research question and will provide single-sentence evidence statements for each. Within this synthesis, information on the volume and quality of evidence per research question will be included, highlighting gaps where they exist.