Covidence is built with two purpose-built templates - Extraction 1 and Extraction 2. They are designed for different data structures and review goals. Choosing the right template depends on how your data is structured and how you plan to synthesize it, ensuring your outputs are rigorous, transparent, and analysis-ready.
Extraction 1 is designed for collecting structured data against defined comparison groups, particularly when you plan to conduct quantitative synthesis or meta-analysis. Its structured framework helps organize results consistently across studies while remaining flexible enough to adapt to different review designs.
Extraction 2 provides a fully customizable template for reviews that require flexible field structures, narrative data capture, or evidence mapping. It is well suited to descriptive, exploratory, or text-heavy reviews where comparison groups are not central to the analysis.
Is Extraction 1 or Extraction 2 better for my review?
Both templates can technically support most review types - the main differentiator is the type of data you’re collecting.
Type of data collected | Recommendation |
Numerical data against groups (Mean, SD, N, effect sizes) | Extraction 1 |
Narrative/descriptive data for mapping or describing evidence | Extraction 2 |
However we know that specific review types tend to have similar data collection needs and approaches to synthesis. The following table describes suitability of both templates based on review context:
Review context | Extraction 1 | Extraction 2 |
Intervention and therapy | Best: Specifically designed for this. Standard PICO structure and RevMan export make analysis easy. | Can be used: But you must build the PICO structure manually and cannot sync directly to RevMan. |
Harm / Etiology | Better: Repurpose the "Intervention" section to capture "Exposures." Ideal for meta-analysis. | Can be used: Good if you have very complex exposure data that doesn't fit a group comparison. |
Qualitative Synthesis | Can be used: Add custom qualitative measures in the "Outcomes" section for themes. | Better: Designed for text-heavy data. Supports large text fields for quotes and narrative findings. |
Scoping Review | Can be used: Good if comparing defined groups (e.g., intervention types, exposure categories) and want structured export. | Better: Allows for custom mapping of broad topics without fixed headers. Consider if the goal is describing breadth rather than numerical comparison |
Narrative Literature Review | Can be used: If structured comparison is needed. | Better: Designed for narrative synthesis without group comparisons. |
Case Series | Better: Highly suitable. You can set up ‘Case’ as an intervention and add "Case 1," "Case 2," etc., dynamically as groups during extraction. | Can be used: But requires a manual setup for every potential case in your template. Wide export sheet depending on the # of cases (all cases per study in a single row). |
Mixed Methods | Better: Customize the "Outcomes" section to capture both numbers and qualitative data. | Can be used: Useful if the qualitative portion is extremely detailed and text-heavy. |
Umbrella / Network Meta-Analysis | Can be used: But difficult to fit complex nested data into the fixed 5-section layout. | Possible: Supports custom fields needed for "reviews of reviews". |
Guidance for using Extraction 1
Extraction 1 is a versatile extraction template suitable for most systematic review types, especially when comparing groups and collecting numerical results for synthesis. Its flexible design and adaptable structure make it useful for both intervention and non-intervention reviews.
It has five core sections that provide a structured starting point for adapting to different research questions and types of evidence synthesis:
Identification
Methods
Population
Interventions
Outcomes
Within these, the "Interventions" section can effectively capture:
Interventions for therapy and treatment reviews
Exposures for harm and etiology studies
Phenomena of interest for qualitative reviews
Cases versus controls for case-control studies
Any comparison groups for comparative designs
View how to use Extraction 1 for non-intervention reviews for more guidance.
Extraction 1 also allows significant flexibility during extraction. You can:
Add intervention/comparison groups dynamically as they appear in studies
Add outcomes and timepoints as reported in individual studies
Handle unexpected study variations without template restructuring
It provides machine-readable exports for RevMan Web, Excel, and CSV formats. This reduces manual data entry errors and saves time during analysis. It is especially useful for reviews that plan to use meta-analysis or quantitative synthesis.
Automation
Covidence provides automatic extraction in Extraction 1 where we can source reliable suggestions, provided that a DOI is available. These suggestions are enabled by default for all users in Extraction 1. Extractors can easily accept or reject these suggestions, saving valuable time and effort, while keeping extractors in full-control (through the tick and cross actions). If no suggestion can be found, the field will remain as a normal input (no suggestion).
Currently, the data sources include:
• Study metadata from external repositories (for both open and closed access studies)
• Large Language Model (LLM) extraction from full-text articles (both open and closed access studies)
Guidance for using Extraction 2
Extraction 2 is a flexible template that gives you complete control over your template structure. It is best when your goal is mapping or describing the evidence, rather than comparing numerical outcomes across groups.
Full Customization: You build the template from scratch with your own headers and sections
Flexible Input Options: Create single-choice or multi-choice dropdown fields to standardize data entry, alongside open text fields for free-form extraction and tables for charting multiple data points across categories (useful for evidence mapping).
Text Intensive: Better for qualitative reviews where you need to extract large amounts of text or quotes.
For reviews with complex data capture needs (e.g. umbrella reviews and prognosis reviews), teams could consider building a custom template in Extraction 2 or using another tool (e.g. Excel).
Feature comparison
The features of Extraction 1 and Extraction 2 are compared in the following table:
Feature | Extraction 1 | Extraction 2 |
Dual reviewer extraction | ✅ | ✅ |
Single reviewer extraction | ✅ | ✅ |
Re-use a data extraction template from another review | ✅ | ✅ |
Create rules to define who must complete extraction, can complete consensus and can edit templates | ✅ | ❌ |
Use of different fields types such as single choice, checkboxes and custom tables | ❌ | ✅ |
Custom judgments in quality assessment template | ✅ | ✅ |
✅ | ❌ | |
Highlight text from study and link to quality assessment judgement | ✅ | ❌ |
Decide whether or not to move studies back to in-progress after updating template | ✅ | ✅ |
Manage reviewers for each study | ✅ | ✅ |
View history of each study | ✅ | ❌ |
✅ | ✅ | |
Export to RevMan (RM5, RevMan Web) | ✅ | ❌ |
Export to Excel | ✅ | ❌ |
Export to CSV | ✅ | ✅ |
Can I switch between Extraction 1 and 2?
Yes, you can switch anytime in settings. This can be useful as a workaround if the tool you are working in does not allow you to view history for example. When you switch to the other tool, all the data in the current tool will be saved. It is not possible, however, to transfer data from one tool to the other.
Try demo review
When you are logged in to Covidence you can try out both versions of extraction in our demo review and decide which one best suits your needs. Just go to the ‘Your reviews’ page and scroll to the bottom to see this option. The demo review is pre-populated with sample data and resets regularly.
