Trial Linking
Many clinical and experimental reviews include the same trial reported across multiple publications - a primary trial paper, a sub-group analysis, a safety report, and so on. Trial linking lets you group these study records under a single trial name, so your team extracts data at the trial level rather than treating each publication independently.
What is a trial?
A trial is a named group that you create to represent a single underlying study or experiment. You give the trial a short identifier (for example, "TRIAL-ABC-001" or "PARTNER-2A") and then link one or more study records from your project to it.
Each study record in your project can be linked to multiple trials if the same publication contributes to more than one analysis. Within each trial, one study record is designated as the main study - the primary source of data for that trial.
Creating a trial
Open the Trial Linking panel
In the Data Extraction section of your project, click the Trials tab. A list of existing trials appears, or an empty state if none exist yet.
Create a new trial
Click New Trial. Enter a trial name or identifier and an optional description, then click Create.
Link studies to the trial
In the trial detail view, click Link Studies. A search panel opens showing all included studies in your project. Search by title or author and click Add next to each study you want to link to this trial.
Designating the main study
Within each trial, you must designate one linked study as the main study. The main study is the primary reference for trial-level extraction - extractors filling in the trial extraction form will see the main study's PDF by default.
To set the main study, click the Set as Main option next to the study record in the trial view. Only one study per trial can be marked as main at a time; setting a new main study removes the designation from the previous one.
Choose the most comprehensive publication as the main study - typically the primary results paper rather than a sub-group analysis or protocol paper.
Toggling data extraction per study
Not every linked study needs to have the extraction form filled in. For example, you may link a protocol paper to the trial for reference, but you only want extractors to extract data from the results papers.
You can toggle data extraction on or off for each study within a trial:
- DE on - the study appears in the extraction queue and extractors must complete the form for it
- DE off - the study is linked for reference only and does not appear in the extraction queue
To toggle, click the DE toggle switch next to a study in the trial detail view.
One study, multiple trials
A single study record can be linked to more than one trial. This is useful when a publication reports data for two separate treatment arms that you are tracking as separate trials, or when a study contributes to both a main analysis and a subgroup analysis.
To add a study to an additional trial, open that trial and link the study using the same Link Studies workflow. The study will then appear in the study list of both trials.
When a study is linked to multiple trials, its extraction form is shared across all of them. Entries made in one trial context are visible when viewing the study in any other trial it belongs to.
Viewing extraction progress by trial
The Trials tab shows an extraction progress indicator for each trial, summarising how many linked studies have completed extraction. Use this view to track trial-level progress rather than individual study progress.
Removing a study from a trial
To unlink a study from a trial, open the trial, find the study in the list, and click Remove. This does not delete the study from your project - it only removes the association between the study and that trial.