Common Mistakes in Scoping Reviews and How to Avoid Them

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-27

Quick Answer

• Define your scoping review question with clear population, concept, and context elements before searching, and register your protocol to prevent aimless literature gathering.
• Build and pilot your data charting form on five or more included sources before full extraction to catch missing fields and inconsistent definitions.
• Report your review against an established reporting guideline and involve a second reviewer in screening and charting decisions to reduce individual bias.

At a Glance

Understanding Scoping Reviews and Their Purpose

A scoping review maps the existing literature on a broad topic to identify key concepts, types of evidence, and gaps. Unlike a systematic review that answers a focused clinical question with a meta-analysis, a scoping review clarifies the extent and nature of research activity. Researchers use scoping reviews to examine emerging topics, clarify definitions, and identify whether a full systematic review is feasible.

The distinction matters for your methods. A scoping review does not typically assess the quality of included studies or synthesize effect sizes. Your goal is to describe what exists, not to determine what works best. This fundamental difference shapes every subsequent decision, from your research question to your data presentation.

Researchers often confuse scoping reviews with systematic reviews or traditional literature reviews. A traditional literature review may be selective and narrative. A systematic review follows a rigorous, reproducible methodology to answer a specific question. A scoping review sits between these, using systematic methods to map evidence without necessarily answering a narrow question. Understanding this positioning prevents you from applying inappropriate quality appraisal requirements or drawing conclusions your design cannot support.

The practical implication for your workflow is that you need a clear articulation of your review's purpose before you begin. Write down whether you are mapping concepts, identifying gaps, or clarifying definitions. This statement guides your inclusion criteria, your search breadth, and your data presentation format. Without this clarity, you risk producing a review that neither maps comprehensively nor answers a focused question.

Mistake 1: Unclear or Overly Broad Research Questions

The most common failure in scoping reviews is a research question that is too vague or too broad to guide decisions. A question like "what do we know about animal welfare" produces an unmanageable body of literature and no clear basis for inclusion or exclusion. Your question must specify the population, the concept being examined, and the context in which it applies.

Use the population, concept, and context framework to structure your question. Population describes the participants or subjects, such as dairy cattle or laboratory mice. Concept identifies the phenomenon of interest, such as pain assessment methods or environmental enrichment strategies. Context specifies the setting, such as intensive production systems or research facilities. This framework forces you to make explicit choices that narrow your scope to something achievable.

Test your question by writing a preliminary search strategy based on it. If your search returns thousands of irrelevant records, your question likely needs refinement. If your search returns almost nothing, your question may be too narrow or your terminology may not match the literature. Adjust your question iteratively before you commit to full screening.

Document your question development process. Record the versions you considered and the reasons for your final choice. This documentation supports the transparency expected in rigorous reviews and helps readers understand your scope decisions. The EQUATOR Network provides access to reporting guidelines that emphasize clear articulation of objectives and questions in the final report.

Mistake 2: Skipping Protocol Development and Registration

A protocol is your preplanned methods document that specifies your research question, search strategy, inclusion criteria, and data extraction approach. Publishing or registering this protocol before you begin screening demonstrates that your methods were determined in advance instead of adjusted to fit what you found.

Without a protocol, you cannot distinguish planned decisions from post hoc changes. This distinction matters for transparency and reproducibility. Reviewers and readers need to know which decisions were made a priori and which emerged during the review process. A registered protocol provides this record.

Your protocol should include your research question, the databases you will search, your search strategy for each database, your inclusion and exclusion criteria, your screening process, and your data charting approach. Specify how many reviewers will screen and extract data and how disagreements will be resolved. Describe your planned approach to presenting results.

Register your protocol in an appropriate registry before you begin screening. This timing is critical. Registration after screening has started weakens the value of the protocol as evidence of preplanned methods. The National Library of Medicine provides access to research methods resources that can help you understand protocol development expectations in the biomedical context.

Mistake 3: Inadequate or Undocumented Search Strategies

A scoping review is only as good as its search. An incomplete search strategy misses relevant studies and produces a biased map of the evidence. A poorly documented search strategy prevents others from reproducing your work and undermines confidence in your conclusions.

Build your search strategy using the key concepts from your research question. Identify synonyms, related terms, and subject headings for each concept. Combine these terms using Boolean operators appropriate to your database. Test your strategy in one database first, examine the results for relevant records, and refine your terms before applying the strategy across all databases.

Search multiple databases relevant to your topic. The specific databases depend on your field, but biomedical and life science topics typically require searching more than one major database. Document which databases you searched, the date of each search, and the exact strategy used in each database. Database interfaces differ, so your strategy may need adaptation for each platform.

Consider supplementary search methods. Hand searching reference lists of included studies, consulting experts, and searching gray literature can identify studies missed by database searches. Document these supplementary methods in your final report so readers understand the full scope of your search effort.

Involve a librarian or information specialist in developing your search strategy. These professionals understand database-specific syntax, subject headings, and search optimization. Their involvement improves search sensitivity and reduces the risk of missing relevant records. The National Library of Medicine offers access to research methods resources that can guide your search development.

Mistake 4: Single Reviewer Screening and Data Extraction

Screening titles and abstracts, then full texts, against your inclusion criteria is a judgment-intensive process. A single reviewer may apply criteria inconsistently or miss relevant studies. Using two independent reviewers reduces individual bias and improves the reliability of your decisions.

Plan your screening process before you begin. Define your inclusion and exclusion criteria in operational terms that reviewers can apply consistently. Train reviewers on the criteria using a sample of records. Pilot the screening process on a set of records and discuss disagreements to calibrate understanding.

During full-text screening, record the reason for each exclusion. This documentation supports the flow diagram required by most reporting guidelines and demonstrates the transparency of your process. Track the number of records identified, screened, excluded, and included at each stage.

Resolve disagreements through discussion or a third reviewer. Document your conflict resolution process in your protocol and final report. The goal is consistency, not necessarily perfect agreement, but you should report your screening process accurately.

Data extraction, called data charting in scoping reviews, also benefits from independent verification. Two reviewers can chart data independently and compare results, or one reviewer can chart data while a second verifies a sample. The level of verification depends on your resources, but some verification is essential for accuracy.

Mistake 5: Poorly Designed Data Charting Forms

The data charting form is your tool for extracting information from included studies. A poorly designed form produces missing data, inconsistent extraction, and a final dataset that cannot answer your research question. Design your form to capture the variables that matter for your review's purpose.

Start with the variables specified in your protocol. Common charting variables include author, year, country, study design, population, concept, context, and key findings. Your specific variables depend on your research question and the nature of the literature you are mapping.

Pilot your charting form on a sample of included studies before full extraction. This pilot reveals missing fields, ambiguous definitions, and variables that are difficult to extract consistently. Revise your form based on pilot results and document the changes you made.

Define each variable clearly in a charting manual or codebook. This manual ensures that all reviewers extract data consistently. Include instructions for handling missing data, multiple outcomes, and studies with unclear reporting.

Consider using a structured form that allows both descriptive and categorical data entry. Categorical fields for study design or population type facilitate quantitative summaries. Free text fields capture nuances that categorical fields miss. Balance structure with flexibility to serve your review's purpose.

Mistake 6: Ignoring Reporting Guidelines

Reporting guidelines specify the minimum information needed to report your research transparently. Using an appropriate reporting guideline improves the completeness and clarity of your final report and helps readers appraise your methods. The EQUATOR Network provides access to a comprehensive collection of reporting guidelines across study types.

Select your reporting guideline early in your review process. The guideline for scoping reviews specifies the items you should report, including your rationale, objectives, protocol, search strategy, screening process, and results presentation. Reviewing the guideline items before you begin helps you plan your methods and documentation.

Use the guideline as a checklist throughout your review, beyond at the end. Check that your protocol addresses the required elements. Verify that your data collection captures the information needed for reporting. Confirm that your final report includes all required items.

Reporting guidelines improve transparency but do not guarantee quality. A report that follows a guideline can still have flawed methods. Use the guideline to ensure complete reporting while maintaining methodological rigor throughout your review process.

The EQUATOR Network also provides resources for understanding reporting guideline development and selection. Familiarize yourself with the guideline relevant to your review type and apply it consistently.

Mistake 7: Neglecting Data Management and Sharing

Scoping reviews generate substantial data, including search records, screening decisions, charted data, and protocol documents. Poor data management risks losing this information and prevents verification of your results. Institutional data management policies increasingly require planning for data preservation and sharing.

Develop a data management plan at the start of your review. Identify the data you will generate, where you will store it, how you will organize it, and who has access. Consider version control for your protocol, search strategies, and charting forms. Back up your data regularly to prevent loss.

The National Institutes of Health data management and sharing policy expects researchers to plan for data preservation and sharing. While this policy applies to NIH-funded research, the principles of good data management apply broadly. Plan for data sharing where appropriate, considering ethical and legal constraints on sharing certain types of data.

Document your data management decisions in your final report. Describe where your data are stored, how they can be accessed, and any restrictions on access. This documentation supports reproducibility and allows others to verify your findings.

Consider using structured data formats that facilitate sharing and reuse. Spreadsheets with clear column headers and consistent coding are more useful than unstructured documents. Document your coding schemes so others can interpret your data.

Mistake 8: Poor Researcher Identification and Authorship Practices

Scoping reviews often involve multiple contributors with different roles. Clear researcher identification and authorship practices prevent disputes and ensure appropriate credit. Publication ethics standards address authorship, contributions, and conflicts of interest.

Maintain an ORCID record that links your research outputs to your identity. ORCID provides a persistent digital identifier that distinguishes you from other researchers with similar names. Include your ORCID identifier in your protocol, publications, and other research outputs.

Discuss authorship early in your review process. Determine who qualifies for authorship based on substantial contributions to conception, design, data collection, analysis, or interpretation. Contributors who do not meet authorship criteria should be acknowledged appropriately.

Document contributions transparently in your final report. Many journals require a contributions statement that specifies each author's role. This transparency supports accountability and prevents disputes about credit.

The Committee on Publication Ethics core practices address authorship, peer review, data access, and conflicts of interest. Familiarize yourself with these standards and apply them throughout your review process. Address potential conflicts of interest before they affect your decisions.

Mistake 9: Inadequate Presentation of Results

A scoping review presents a map of the evidence, not a synthesis of effect sizes. Your results presentation should describe the volume, nature, and characteristics of the included studies. Poor presentation obscures your findings and fails to serve your review's purpose.

Present your screening results in a flow diagram that shows records identified, screened, excluded, and included at each stage. This diagram provides transparency about your process and allows readers to assess potential bias.

Summarize the characteristics of included studies in tables. Report the distribution of studies by year, country, study design, population, and other relevant variables. These summaries give readers a clear picture of the evidence landscape.

Present your findings narratively, organized around the key concepts in your research question. Describe what the literature covers, where the evidence is concentrated, and where gaps exist. Use tables and figures to support your narrative without overwhelming it.

Avoid drawing conclusions about effectiveness or quality that your scoping review design cannot support. Your role is to describe the evidence, not to evaluate it. Clearly distinguish your descriptive findings from any implications you identify for future research.

Mistake 10: Failing to Document Limitations and Gaps

Every scoping review has limitations, and failing to acknowledge them undermines the credibility of your work. Transparent reporting of limitations helps readers interpret your findings appropriately and identifies areas for future research.

Acknowledge limitations in your search strategy, such as language restrictions, database coverage, or publication date limits. Describe how these limitations might affect your findings. Acknowledge limitations in your screening and charting processes, such as the number of reviewers or the reliability of data extraction.

Identify gaps in the evidence that your review reveals. These gaps may relate to populations, concepts, contexts, or study designs that are underrepresented in the literature. Describe these gaps clearly and suggest directions for future research.

Distinguish between gaps in the evidence and limitations of your review. A gap is an area where evidence is missing. A limitation is a constraint on your review's methods. Both are important to report, but they serve different purposes.

The reporting guideline you selected will specify the limitations you should address. Use the guideline to ensure you have considered all relevant limitations and reported them transparently.

Practical Implementation Steps

Implementing rigorous scoping review methods requires a structured approach. Follow these steps to avoid common mistakes and produce a defensible review.

First, articulate your research question using the population, concept, and context framework. Write your question explicitly and test it against a preliminary search. Refine your question until it is specific enough to guide decisions but broad enough to map the relevant literature.

Second, develop and register your protocol before screening begins. Include your research question, search strategy, inclusion criteria, screening process, and data charting approach. Register your protocol in an appropriate registry and document any subsequent changes.

Third, build and test your search strategy with librarian input. Search multiple databases, document your strategies, and consider supplementary search methods. Record the date and results of each search.

Fourth, pilot your screening and charting processes. Train reviewers on your criteria, pilot screening on a sample of records, and pilot your charting form on a sample of included studies. Revise your processes based on pilot results.

Fifth, conduct screening and charting with independent reviewers and conflict resolution. Document your decisions and track excluded records with reasons. Verify data extraction for accuracy.

Sixth, present your results transparently using a flow diagram, summary tables, and narrative description. Report against your selected guideline and acknowledge limitations and gaps.

Seventh, manage your data throughout the process. Store, organize, and back up your data. Plan for data sharing where appropriate.

Records and Measurements

Maintain detailed records throughout your scoping review to support transparency and reproducibility. Your records should document every decision you make and every step you take.

Record your search strategies for each database, including the date of each search and the number of results. Save your search strategies in a format that can be reproduced. Document any changes to your search strategy and the reasons for those changes.

Track your screening decisions at each stage. Record the number of records identified, screened, excluded, and included. Document the reasons for exclusion at the full-text stage.

Maintain your charting form and codebook as living documents. Record any changes you make to variables or definitions during the review process. Document the version of your charting form used for each study.

Keep your protocol and any amendments. If you deviate from your protocol, document the deviation and the reason. This documentation supports the distinction between planned and post hoc decisions.

Store your data in a structured format that supports analysis and sharing. Use consistent coding and clear documentation. Back up your data regularly to prevent loss.

Common Failure Patterns

Recognizing common failure patterns helps you avoid them in your own review. These patterns recur across scoping reviews and reflect predictable challenges.

The scope creep pattern occurs when the research question expands during the review process. Researchers add new concepts or populations as they encounter interesting literature. This expansion produces an unmanageable review and unclear findings. Prevent scope creep by committing to your protocol and documenting any necessary changes.

The search inadequacy pattern occurs when researchers search too few databases or use incomplete search strategies. This pattern produces a biased map of the evidence and misses relevant studies. Prevent search inadequacy by involving a librarian and testing your strategies.

The extraction inconsistency pattern occurs when reviewers extract data differently from the same studies. This pattern produces unreliable data and undermines your findings. Prevent extraction inconsistency by piloting your charting form and using a detailed codebook.

The reporting opacity pattern occurs when researchers fail to document their methods transparently. This pattern prevents readers from appraising the review and reproducing the methods. Prevent reporting opacity by using a reporting guideline and documenting all decisions.

The overreach pattern occurs when researchers draw conclusions their scoping review design cannot support. This pattern misleads readers and undermines the credibility of the review. Prevent overreach by clearly distinguishing description from evaluation.

Welfare and Safety Context

Scoping reviews in animal-related fields raise specific considerations that researchers should address. These considerations relate to the ethical conduct of research and the responsible use of animal-related evidence.

If your scoping review addresses animal welfare topics, ensure your review methods are rigorous enough to support conclusions that may inform welfare decisions. A poorly conducted review can produce misleading maps of evidence that misguide policy or practice.

Consider the ethical dimensions of your review topic. If your review addresses controversial topics, such as animal testing or intensive production systems, maintain objectivity in your methods and reporting. Your role is to map the evidence, not to advocate a position.

If your review involves human participants or sensitive data, consider the ethical and regulatory requirements that apply. While scoping reviews typically use published literature, some reviews may access unpublished data or involve stakeholder consultation. Address these considerations in your protocol.

The National Institutes of Health provides guidance on responsible conduct of research that applies broadly to research practices. Familiarize yourself with these expectations and apply them to your review process.

Professional Escalation Criteria

Some situations in scoping reviews require escalation to supervisors, librarians, or ethics committees. Recognize these situations and seek appropriate guidance.

Escalate to a librarian or information specialist if you cannot develop a search strategy that returns relevant results. A search that returns almost nothing or thousands of irrelevant records suggests a problem with your strategy or terminology. Professional search expertise can resolve these issues.

Escalate to your supervisor or research team if you encounter substantial disagreement between reviewers that cannot be resolved through discussion. Persistent disagreement may indicate ambiguous criteria that need revision or additional training needs.

Escalate to an ethics committee or institutional official if your review raises ethical concerns, such as access to sensitive data or involvement of vulnerable populations. While scoping reviews typically use published literature, some reviews may raise ethical considerations that require institutional review.

Escalate to a statistician or methods expert if you are uncertain about how to present or analyze your data. While scoping reviews are primarily descriptive, some presentations may benefit from expert input.

Escalate to a publication ethics advisor if you encounter authorship disputes, suspected misconduct, or other ethical concerns. The Committee on Publication Ethics provides resources for addressing these situations.

Frequently Asked Questions

What is the difference between a scoping review and a systematic review?

A scoping review maps the extent and nature of evidence on a broad topic, while a systematic review answers a focused question with rigorous synthesis. Scoping reviews do not typically assess study quality or combine effect sizes. Your choice depends on whether you need to map evidence or answer a specific question.

How many databases should I search for a scoping review?

The number of databases depends on your topic and field. Most scoping reviews search multiple major databases relevant to their discipline. Consult a librarian to identify the databases most likely to contain relevant literature for your topic.

Do I need to register my scoping review protocol?

Protocol registration is strongly recommended for scoping reviews. Registration before screening begins demonstrates that your methods were preplanned and supports transparency. Check whether your target journal or funder requires protocol registration.

How do I develop a data charting form?

Start with the variables specified in your protocol and relevant to your research question. Pilot your form on a sample of included studies and revise based on what you learn. Create a codebook that defines each variable and provides instructions for extraction.

Should I assess the quality of studies in a scoping review?

Quality appraisal is not typically required in scoping reviews because the purpose is to map evidence, not evaluate it. Some scoping reviews may include a descriptive assessment of study characteristics, but this differs from formal quality appraisal. Follow your protocol and reporting guideline.

How do I present the results of a scoping review?

Present your screening results in a flow diagram and summarize study characteristics in tables. Describe the evidence narratively, organized around your research question's key concepts. Identify gaps in the evidence and avoid drawing conclusions about effectiveness that your design cannot support.

What reporting guideline should I use for my scoping review?

The EQUATOR Network provides access to reporting guidelines for various study types. Select the guideline appropriate for scoping reviews and use it throughout your review process. Review the guideline items early to plan your methods and documentation.

How do I handle disagreements between reviewers?

Plan your conflict resolution process in your protocol. Common approaches include discussion between reviewers, involvement of a third reviewer, or consensus meetings. Document your process and the outcomes of disagreements.

Using the Evidence

Related Articles

• Common Mistakes in Meta-Analysis and How to Avoid Them
• Ethical Concerns in Research: Common Pitfalls and How to Avoid Them
• Common Limitations in Research: Examples and How to Address Them
• Ethical Issues in Informed Consent: Common Pitfalls and How to Avoid Them
• Clinical Research Coordinator Interview Questions and How to Answer Them

References and Further Reading

• Research Methods Resources. National Library of Medicine.
• EQUATOR Network. EQUATOR Network.
• Core Practices. Committee on Publication Ethics.
• NIH Grants and Funding. National Institutes of Health.
• ORCID for Researchers. ORCID.
• Data Management and Sharing Policy. National Institutes of Health.
• NCBI Literature Resources. National Center for Biotechnology Information.
• PubMed. National Library of Medicine.

This article is educational and does not replace institutional policy, professional advice, or applicable safety and regulatory requirements.