> For the complete documentation index, see [llms.txt](https://docs.nested-knowledge.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nested-knowledge.com/review-workflow/study-inspector/filter-studies/filters-available-in-study-inspector.md).

# Filters Available in Study Inspector

Learn what filters are available and how they can be applied.

Every filter you can add in Study Inspector is listed here, grouped by area: bibliographic detail, data gathered during review, workflow status, search origin, and, on Enterprise nests, reviewer allocation. For how to add, layer, negate, and save filters, see [Filter Studies](/review-workflow/study-inspector/filter-studies.md); this page is the reference list of what's available and when you'd reach for each one.

| Category      | Covers                                                                                |
| ------------- | ------------------------------------------------------------------------------------- |
| Bibliographic | Titles, authors, dates, journal detail, identifiers, and usage rights                 |
| Gathered      | Tags, tag contents, critical appraisal ratings, extracted data elements, and comments |
| Workflow      | Screening status, reviewer and adjudicator activity, and module completion            |
| Search        | Where and when a study entered the nest                                               |
| Allocation    | Reviewer assignments (Enterprise subscriptions with Allocation turned on)             |

### Bibliographic Filters

<details>

<summary>Title/Abstract</summary>

Searches study titles, abstracts, or both for keywords, phrases, or terms, independent of full text upload status. Choose title only, abstract only, or both. For example, search "randomized controlled trial" in both fields to surface RCTs that might not yet be tagged as such.

</details>

<details>

<summary>Full Text Search</summary>

Searches the full text of uploaded PDFs for keywords, phrases, or terms, supporting exact phrase matching, case sensitivity, and wildcard or Boolean operators. Effectiveness depends on how many full texts are uploaded in your nest. For example, search "adverse events" OR "side effects" to find safety outcomes not captured in an abstract.

</details>

<details>

<summary>Authors</summary>

Filters by the first author's name, with exact, partial, or case-insensitive matching. For example, filter to a specific first author to gather every study from a known research group for expert consultation.

</details>

<details>

<summary>Author Affiliation</summary>

Filters by institutional affiliation; data quality depends on how complete the underlying bibliographic records are. For example, filter to "Pharmaceutical" or "Pharma" to identify industry-sponsored research.

</details>

<details>

<summary>Publication date</summary>

Filters to a date range: before a date, after a date, between two dates, or an exact year. For example, filter to studies published after 2020 to focus on current evidence.

</details>

<details>

<summary>DOI</summary>

Filters by Digital Object Identifier, matched exactly or partially, with multiple DOIs supported at once. For example, search a specific DOI to confirm whether a study is already in the nest before adding it again.

</details>

<details>

<summary>PubMed ID</summary>

Filters by PMID, single or batch. For example, input a set of PMIDs identified through an external search to quickly locate that exact group of studies.

</details>

<details>

<summary>PMC ID</summary>

Filters by PubMed Central ID, single or batch. For example, filter to studies with a PMC ID to prioritize ones with freely available full text.

</details>

<details>

<summary>Embase ID</summary>

Filters by Embase database identifier, most relevant when your search included Embase imports. For example, filter to Embase IDs to identify records unique to Embase and not found in other databases.

</details>

<details>

<summary>NCT Number</summary>

Filters by ClinicalTrials.gov registration number, single or batch. For example, filter by NCT number to confirm a published study matches its registered trial protocol.

</details>

<details>

<summary>Ref ID</summary>

Filters by Nested Knowledge's internal reference ID, assigned by upload order and preserved even if a record is later deleted. Supports a single ID, a range (for example, 1 to 100), or a discrete list. For example, filter to a Ref ID range to process studies in upload order during systematic screening.

</details>

<details>

<summary>External ID</summary>

Filters by a custom identifier you've configured on a study's bibliographic data, useful for institutional or project-specific numbering. For example, use external IDs to track studies against an internal library numbering system.

</details>

<details>

<summary>Journal</summary>

Filters by publication venue, matched exactly, partially, or by common abbreviation. For example, filter to a small set of high-impact journals to prioritize those publications first.

</details>

<details>

<summary>Issue</summary>

Filters by issue number within a volume, alone or combined with journal and volume. For example, filter to a supplement issue to surface conference abstracts, which are often published that way.

</details>

<details>

<summary>Volume</summary>

Filters by journal volume, alone or combined with journal. For example, filter across a range of volumes to see how a journal's coverage of a topic evolved over time.

</details>

<details>

<summary>ISSN</summary>

Filters by a journal's International Standard Serial Number, recognizing both print and electronic forms. For example, use ISSN to disambiguate two journals with similar or shared names.

</details>

<details>

<summary>Language</summary>

Filters to English, non-English, or a specific language where available in the metadata. For example, include non-English studies deliberately when assessing potential language bias in a review.

</details>

<details>

<summary>Keywords</summary>

Filters by bibliographic keywords supplied by the source database or publisher, with Boolean support across multiple keywords. For example, filter by a MeSH-style subject term such as "hypertension" to find studies indexed under that concept.

</details>

<details>

<summary>Publication Type</summary>

Filters by classifications such as clinical trial, systematic review, or case report, where the source database provides them. For example, filter to "Clinical Trial" to focus on interventional research for a treatment-effectiveness review.

</details>

<details>

<summary>Bibliographic Status</summary>

Filters to records where a specific field, such as Abstract or DOI, is empty or not empty. For example, filter to records with an empty DOI field to prioritize bibliographic cleanup.

</details>

<details>

<summary>Publication Update</summary>

Filters to studies flagged by their source database as retracted or corrected. For example, filter to retracted studies to exclude discredited research before finalizing an evidence base.

</details>

<details>

<summary>Open Access Full Text</summary>

Filters to records with an open access full text available through Unpaywall, whether or not that full text has actually been uploaded to the nest yet, which distinguishes this filter from Full Text Status. If a bulk Unpaywall import doesn't capture every available PDF, use this filter afterward to find and manually upload the remainder.

</details>

<details>

<summary>Usage Rights</summary>

Available only with a connected usage-rights source such as [**CCC RightFind**](/integrations/ccc-rightfind.md). Filters by the rights held for a study's full text, Print, Digital Use, AI/ML Use, or Reactive Sharing, each with a status of Grant, Deny, or Unknown. For example, filter to AI/ML Use: Grant to isolate the records you're licensed to process before running an AI tool such as [**Adaptive Smart Tags**](/review-workflow/tagging/ai-tools-in-tagging/adaptive-smart-tags.md) over your included studies.

</details>

<details>

<summary>Usage Rights Ineligibility</summary>

Available only with a connected usage-rights source such as [**CCC RightFind**](/integrations/ccc-rightfind.md). Filters to records the connected source couldn't return rights for at all, distinct from records explicitly denied a right. For example, use this filter to route records needing a manual rights check, separate from ones already assessed and denied.

</details>

### Gathered

<details>

<summary>Question Completion</summary>

Requires question-type tags configured through [**Configure Tagging**](/review-workflow/tagging/configure-tagging.md). Filters by a tagging question's completion state, Relevant, Not Relevant, or Unanswered, for one question or across all of them. For example, select "All" and Unanswered to surface every record with outstanding tagging questions, picking up extraction exactly where it left off.

</details>

<details>

<summary>Tag</summary>

Filters to studies assigned a specific tag or any of its child tags. For example, filter to a population tag such as "Elderly" to focus on geriatric-population research.

</details>

<details>

<summary>Tag Contents</summary>

Searches the free text or table content recorded under any tag, across every study. For example, search "primary outcome" within tag contents to find studies with a detailed outcome definition already captured.

</details>

<details>

<summary>Critical Appraisal</summary>

Available when a [**Critical Appraisal**](/review-workflow/critical-appraisal.md) tool is configured for the nest. Filters by assigned risk-of-bias or quality level, overall or by domain. For example, filter to "Low risk" studies to build a sensitivity analysis using only the highest-quality evidence.

</details>

<details>

<summary>Data Element</summary>

Available when [**Meta-Analytical Extraction**](/review-workflow/meta-analytical-extraction.md) is configured. Filters to studies with a specific data element already extracted. For example, filter to studies with "Effect Estimates" extracted to identify candidates for quantitative synthesis.

</details>

<details>

<summary>Intervention</summary>

Available when [**Meta-Analytical Extraction**](/review-workflow/meta-analytical-extraction.md) is configured. Filters by a categorized intervention. For example, filter to two specific interventions to compare therapeutic approaches directly.

</details>

<details>

<summary>Comments</summary>

Searches reviewer comments and annotations across all studies, with support for filtering by author, timestamp, or module. For example, search "contact author" in comments to identify studies that need follow-up before finalizing.

</details>

<details>

<summary>Comment Resolution Status</summary>

Returns any study with at least one comment matching the resolution status you select, resolved or unresolved. Useful for finding every study that still has an open comment attached.

</details>

### Workflow

Some workflow filters only appear in certain screening modes, or when specific modules are configured.

<details>

<summary>Reviewer Screening</summary>

Available only in **Dual Screening**. Filters by an individual reviewer's decision, including [**Robot Screener**](/review-workflow/screening/exclusion-based-screening/robot-screener.md) decisions where used. For example, filter to one reviewer's Include decisions to review what they advanced for quality assessment.

</details>

<details>

<summary>Screening Adjudicated By</summary>

Available only in Dual Screening with adjudication. Filters by which adjudicator resolved a disagreement. For example, filter by adjudicator to examine conflict-resolution patterns over time.

</details>

<details>

<summary>Screening Agreement</summary>

Available only in Dual Screening. Filters by whether two reviewers agreed: Include/Include, Exclude/Exclude, or Disagree. For example, focus on "Disagree" studies to identify cases that need clearer screening guidance.

</details>

<details>

<summary>Reviewer AB Screening</summary>

Available only in Dual Two Pass Screening. Filters by an individual reviewer's abstract-level decision. For example, filter to a reviewer's "Advance" decisions to see which studies progressed to full text review.

</details>

<details>

<summary>Reviewer FT Screening</summary>

Available only in Dual Two Pass Screening. Filters by an individual reviewer's full-text-level decision. For example, filter to a reviewer's Include decisions to identify studies advancing to data extraction.

</details>

<details>

<summary>Abstract Screening</summary>

Available only in Dual Two Pass Screening. Filters by a study's final abstract-level status: advanced, excluded, or pending. For example, filter to "Advanced to full text" to quantify how many studies progressed past abstract screening.

</details>

<details>

<summary>AB Screening Adjudicated By</summary>

Available only in Dual Two Pass Screening with abstract-level adjudication. Filters by which adjudicator resolved an abstract-level disagreement.

</details>

<details>

<summary>FT Screening Adjudicated By</summary>

Available only in Dual Two Pass Screening with full-text-level adjudication. Filters by which adjudicator made the final inclusion or exclusion call.

</details>

<details>

<summary>AB Screening Agreement</summary>

Available only in Dual Two Pass Screening. Filters by reviewer agreement at the abstract level: Advance/Advance, Exclude/Exclude, or Disagree.

</details>

<details>

<summary>FT Screening Agreement</summary>

Available only in Dual Two Pass Screening. Filters by reviewer agreement at the full-text level: Include/Include, Exclude/Exclude, or Disagree.

</details>

<details>

<summary>Final Screening</summary>

Filters by a study's ultimate screening status: included, excluded (any reason or a specific reason code), or pending. Complexity increases in Dual and Dual Two Pass modes, where this reflects the final decision after all review phases. For example, filter to "Included" to identify the final study set for extraction and analysis.

</details>

<details>

<summary>Module Status</summary>

Filters by completion status in Tagging, MA Extraction, or Critical Appraisal, alone or combined. For example, filter to "MA Extraction: Incomplete" to identify studies still needing data extraction.

</details>

<details>

<summary>Screening Criteria</summary>

Available only under **Criteria-Based Screening**. Filters by the answer recorded for a specific criterion. Add one filter per criterion to isolate an exact combination of answers. For example, combine No on your population criterion with Yes on every other criterion to surface records that fail only on population, ready to exclude together through **Bulk Actions**.&#x20;

</details>

<details>

<summary>Full Text Status</summary>

Filters by whether and how a PDF has been uploaded and attached, tracking availability and source rather than review completion. For example, filter to "PDF upload pending" to manage full text acquisition efforts.

</details>

<details>

<summary>Supplemental Materials</summary>

Filters by the number of uploaded supplemental files, as a specific count, a range, or simply present or absent. For example, filter to studies with more than three supplemental materials to prioritize the most thoroughly documented ones.

</details>

<details>

<summary>Full Text Review</summary>

Filters by whether the Full Text Review checkbox has been marked during screening. For example, filter to unreviewed studies to assign remaining full text review work.

</details>

<details>

<summary>Advancement or Inclusion Probability</summary>

Available when probability scoring is enabled. Filters by a study's calculated advancement or inclusion probability, by range or threshold. For example, filter to above 80% probability to prioritize likely includes for senior review.

</details>

<details>

<summary>Reviewer Count</summary>

Available only in Dual and Dual Two Pass Screening. Filters by how many reviewers have completed a module for a study. For example, filter to studies with fewer than two reviewers to identify ones needing additional review.

</details>

### Search

<details>

<summary>Literature Search</summary>

Filters by a study's origin: a specific database search, an expert addition, or a hand search. For example, compare "PubMed search" against "Embase search" to assess each database's contribution to the nest.

</details>

<details>

<summary>Related Report Family</summary>

Available when related report grouping is enabled. Filters to every publication belonging to the same underlying research project. For example, filter to a named trial family to examine every publication from that one clinical trial.

</details>

<details>

<summary>Related Report Type</summary>

Available when related report classification is enabled. Filters by a report's role within its family: primary, secondary, sub-study, or unassigned. For example, filter to "Primary" reports to focus on each family's main characteristics and outcomes.

</details>

<details>

<summary>Time of Retrieval</summary>

Filters by when a study was imported into the nest, before, after, or between dates. For example, filter to studies retrieved after your last search update to review what's new.

</details>

### Allocation

Available only on Enterprise subscriptions with Allocation turned on.

<details>

<summary>Allocated To</summary>

Filters by which user a study is assigned to, per module. For example, filter to a specific reviewer's screening assignments to monitor their progress, or filter to unallocated studies to assign outstanding work.

</details>

<details>

<summary>Allocated Count</summary>

Filters by how many studies are allocated to users within a module. For example, filter to reviewers with unusually high counts to identify workloads that need redistributing.

</details>

### FAQs

<details>

<summary>Can I filter by more than one tag at once?</summary>

Yes. Add multiple Tag filters and combine them, or use [Advanced Study Inspector](/review-workflow/study-inspector/filter-studies/advanced-study-inspector.md) to control whether they combine with AND or OR or NOT.

</details>

<details>

<summary>What's the difference between Tag and Tag Contents?</summary>

Tag filters to studies where a tag has been applied at all. Tag Contents searches the actual text or table data recorded under a tag, which is useful when you're looking for a specific detail rather than just presence or absence.

For example, when you filter to the Core Smart Tags tag: **Study Location,** use Tag Contents. The list of countries is built as content options.

</details>

<details>

<summary>Why don't I see Allocation filters in my nest?</summary>

[**Allocation**](/collaborate/allocation.md) is an Enterprise feature that also needs to be turned on for the nest. Without both, those filters don't appear.

</details>

<details>

<summary>Why don't I see filters like Reviewer Agreement or AB Screening?</summary>

These depend on your screening configuration. Dual-mode filters only appear in Dual Screening, and Two Pass-specific filters only appear in Dual Two Pass Screening.

</details>

### Next Steps

<table data-card-size="large" data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><i class="fa-filter">:filter:</i><br><strong>Filter Studies</strong></td><td>Add, combine, exclude, and save filters.</td><td><a href="/review-workflow/study-inspector/filter-studies.md">Filter Studies</a></td></tr><tr><td><i class="fa-code-branch">:code-branch:</i><br><strong>Advanced Study Inspector</strong></td><td>Build Boolean queries with AND and OR.</td><td><a href="/review-workflow/study-inspector/filter-studies/advanced-study-inspector.md">Advanced Study Inspector</a></td></tr><tr><td><i class="fa-list-check">:list-check:</i><br><strong>Bulk Actions</strong></td><td>Update the studies in your current filter.</td><td><a href="/review-workflow/study-inspector/bulk-actions.md">Bulk Actions</a></td></tr></tbody></table>


---

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