Evidensia’s approach and methodology

We select and carefully organise evidence so you can find what you need.

Download the full Evidensia evidence typology document:

Evidensia Evidence Typology

Site scope

Evidensia’s overall focus is research on the sustainability impacts of various supply chain initiatives and tools. A focus on impacts means we primarily seek content that is based on research evaluating the impacts and effectiveness of these initiatives. Many users also seek more basic information about how certain approaches or tools function and the contextual differences in which they operate. Evidensia’s content scope includes such material but clearly identifies it as being distinct from evidence. Our evidence typology (detailed below) guides the user at every point in the site.

The supply chain initiatives and tools or ‘sustainability approaches’ that we include on the site are:

Bans, moratoria, and multi-party agreements (for specific commodities/areas); Jurisdictional approaches; Public or quasi-public sustainability standards; Specific global or regional implementation norms for responsible supply chains; Specific national plans, policies and platforms; Supplementary voluntary standards systems (VSS) tools; Supply chain investment programs; Sustainability performance and progress reporting; Sustainability requirements within trade or procurement policies; Sustainable sourcing codes; Voluntary Sustainability Standards

This list includes the major types of supply chain and market-based sustainability approaches operational today and will be updated as this field of practice expands. You can filter based on approach type and specific tool of interest on all our interactive features.

The site covers a wide range of sustainability issues and topics of interest. These are organised into twelve major issues with each issue encompassing a range of topic or outcomes of interest within it. The twelve issues are:

Child rights and wellbeing; Climate change; Consumers and supply chains; Forests and other ecosystems; Freshwater and oceans; Health and wellbeing; Livelihoods; Participant costs and benefits; Pesticides, fertilizers and soil; Plant and wildlife conservation; Rights of indigenous peoples and local communities; Wages and workers’ rights

Click on the issues tab in the main site menu to browse Evidensia through this lens.

Finally, as a general rule, Evidensia hosts content with a ten year cut-off from date of publication meaning that all content on the site is ten years or less in age. For certain content types such as operational information, learnings from the field and blogs, we adopt a shorter cut-off date.

What’s on the site and what’s not

Evidensia follows an open source principle to sourcing content that is in line with the scope set out above. Our vision is to make Evidensia a comprehensive library of all relevant research on the impacts and effectiveness of supply chain sustainability tools. We are however only at the start of this journey and are keen to work with researchers and other organisations to progressively fill the gaps in our site content and knowledge gaps in the field. We welcome relevant submissions by organisations and researchers to achieve this.

The Evidensia team actively tracks research activity in this field to identify relevant content for the site and secure permissions from the authors and publishers to host it here. We also procure content through our direct outreach and engagement with researchers and our academic partners. All content that is selected or submitted to the site is screened for basic research quality norms that includes clear information on the research’s design, data collection and analysis methodology as well as clarity on publishers. We will only reject content that is either irrelevant to the site or does not meet these basic quality criteria.

We understand that there are different types of evidence as determined by a range of study methods and our screening is only to establish credibility and clarity about the content shared on the site. Once screened, all content is categorised based on our detailed evidence typology that determines what type of evidence it is and how it is represented on the site.

Each resource on the site is then coded according to our data structure that captures key details about the resource and feeds into the site’s various features and functionalities. As coding may take some time, there may be some lag between when a study is submitted to us an when it is uploaded on to the site.

Read more below on the specific scope and methodology used for each of our main features.

Online Library - types of evidence and information included

Evidensia’s online library is the storehouse for all the site’s content. It includes content from all the six evidence types in our typology which are:

  • Synthesis papers – Research that synthesises results from multiple individual studies
  • Empirical studies – Data-driven research at the field level
  • Monitoring reports – Trends over time, drawn primarily from internal monitoring activities
  • Modeling studies – Research that uses modelling techniques to assess patterns or make broader inferences
  • Descriptive information – Documents or other resources explaining concepts, approaches, programmes and the operation of tools
  • Briefings or opinions – Opinion pieces, briefing papers, blogs and other resources

The Online Library’s filtering function helps you find the type of evidence you are looking for.  For example, if you want empirical studies with original field-level data, you can filter your search to only show that type of research.  You can filter even further and retain only studies that include a control group or search for very specific kinds of studies such as randomised controlled trials. If you’re interested in the more basic literature reviews or advanced modeling studies, you can search for those too.

For more information, download the full evidence typology document

Evidensia’s online library includes resources in many formats so you can go directly to the format that you prefer.

  • Documents (includes full research reports, shorter briefings and summaries, academic journal articles, books and book chapters, conference proceedings and papers)
  • Images and Infographics
  • Podcasts
  • Webinars
  • Videos
  • Other resources such as blogs and analytical articles

Knowledge Matrix and Geographic Map – types of evidence included

Our Knowledge Matrix and Geographic Map are tools designed to give the user the lay of land on what research and evidence is available on different approaches, issues or sectors of interest. The Knowledge Matrix does this with simple tables that plot evidence availbility in two modes that allows users to review the relative availablity of evidence and locate what they need easily. The Geographic Map does this by plotting the same information on a map with pins indicating the geographic focus of the study.

As the aim of these tools is to provide an overview of what evidence there is on impacts and effectiveness, we include only the following major evidence types of our typology in this namely:


  • Synthesis papers – Research that synthesises results from multiple individual studies
  • Empirical studies – Data-driven research at the field level
  • Monitoring reports – Trends over time, drawn primarily from internal monitoring activities
  • Modeling studies – Research that uses modelling techniques to assess patterns or make broader inferences

Evidensia Visual Summaries – evidence included and methodology

A key feature of this site is our visual summaries, which depict the results of important quantitative research visually. Evidensia’s visual summaries are generated from data gathered through specific research synthesis efforts, undertaken by us or other researchers, that identify and synthesize available evidence on a particular topic or intervention.  This feature is inspired by recent efforts by researchers and practitioners to find innovate ways of communicating results from systematic reviews and other synthesis research efforts – notably the work on conservation effectiveness led by Zuzana Burivalova.

The user can access the report associated with each research review easily on the page via the ‘View associated synthesis report’ link. The user can choose to see a visual summary of the studies covered by one research synthesis effort, or can see a combined view with the results associated with all research synthesis efforts currently available on Evidensia.

Synthesis research attempts to answer a research question by drawing together the results or findings from all relevant primary literature in a robust and coherent way. Synthesis research can be conducted in many ways, using different quality parameters and screening filters to select the relevant primary literature. For example, systematic reviews follow a rigorous, pre-determined protocol for identifying, selecting and evaluating the reviewed studies, while narrative reviews and literature reviews typically do not contain as many such protocol elements. For details on the specific methodology adopted for each synthesis report produced by Evidensia, we encourage readers to carefully read each report’s methodology section.

All of Evidensia’s visual summaries show the results of empirical studies that compare a treatment group to a robust control group, and that draw inferences using quantitative statistical tools. In practical terms, this means that the visual summaries include the results of studies that have the following study designs: a) randomized control trials; b) quasi-experimental studies that use matching techniques to ensure an unbiased control group; c) quasi-experimental studies with an unmatched control group and data collected at two points in time; d) quasi-experimental studies with an unmatched control group and data collected at one point in time, and d) modeling studies that compared treatment and control scenarios. Results from all of the above study designs are shown in the visual summaries when the “all results” button is pressed; results from only a) and b) are shown when the “strongest results” button is pressed.

All results included in the visual summaries use statistical methods to evaluate whether or not an intervention has an effect on the topic of interest. The determination of whether the intervention performed better, worse, or the same as the control group is based on the conclusions arrived at by the study’s author(s), based on statistical analysis.

What does all this mean in practice? Let’s examine a made-up study that looks at the effects of a hypothetical voluntary sustainability system – let’s call it the ABC system – on the yield and household income of smallholder cocoa farmers. Evidensia researchers read the study and learn that the study authors selected a treatment group of ABC-certified farmers, and then used propensity-score matching to select an equivalent control group. This means that the study falls into study design category “b” above and is therefore included in our review. Further reading reveals that the researchers measured farm yield and net household income, which are both outcomes included in the Evidensia visual summary under the issue heading “Participant costs and benefits.” The authors state that they compared these outcomes on treatment and control groups, and that the statistics reveal that farm yield was higher on certified farms, but that net household income was no different. Given these findings, the first result would show up in the visual summary as a solid green square beside the outcome “yield,” and the second result as a solid blue square beside the outcome “net household income.” And because of the study design used, these two results would show up both when the “all results” button is pressed and when the “strongest results” button is pressed.

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