Updating a systematic review is a valuable contribution! The first and most critical step is indeed to thoroughly understand the original review's methodology. Here's a systematic approach to obtain the original search strategies and eligibility criteria:

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Phase 1: Exhaustive Search of the Published Article and Supplementary Materials

This is your primary and most accessible source.

• Read the Main Article Thoroughly:


• Methods Section: This is where the authors must describe their approach. Look for subsections on:


• Search Strategy:


• List of databases searched (e.g., PubMed, Embase, Cochrane CENTRAL, Web of Science, CINAHL).


• Date ranges of the search.


• Key search terms or keywords used (often a truncated list).


• Mention of Boolean operators (AND/OR), truncation (*), wildcard (?), field codes (e.g., [tiab] for title/abstract).


• Information on grey literature searches (e.g., clinical trial registries, conference proceedings, theses, hand-searching reference lists).


• Crucially, look for statements like: "The full search strategy for PubMed is provided in Appendix 1," or "See Supplementary Material for complete search strings."


• Eligibility Criteria:


• This is typically described using the PICO (Population, Intervention, Comparator, Outcome) or PEO (Population, Exposure, Outcome) framework, or sometimes PICOS (PICO + Study Design).


• Participants/Population: Who was studied? (e.g., adults with type 2 diabetes, children aged 6-12).


• Intervention/Exposure: What was the focus? (e.g., a specific drug, a behavioral therapy, environmental pollutant).


• Comparator (if applicable): What was the intervention compared against? (e.g., placebo, standard care, no intervention).


• Outcomes: What were the primary and secondary outcomes measured? (e.g., blood pressure, quality of life, adverse events).


• Study Design: What types of studies were included? (e.g., randomized controlled trials, observational studies, cohort studies).


• Language: Were there language restrictions? (e.g., English only).


• Publication Date: Were there date restrictions? (e.g., published after 2000).


• Publication Status: Were only published studies included, or grey literature too? (e.g., "peer-reviewed articles only," or "including conference abstracts").


• Scrutinize Appendices and Supplementary Materials:


• Check the end of the main article: Many journals include appendices here.


• Look for links on the journal's website: Most journals host supplementary files online, often linked directly from the article's landing page. These might be PDF documents, Word files, or Excel sheets.


• What to look for:


• Full Search Strategies: This is the most likely place to find the complete, line-by-line search strings for each database used. This is gold! It will show you exactly how they combined terms, applied field codes, and used limits.


• Detailed Eligibility Tables: Sometimes a table outlining inclusion and exclusion criteria with specific examples is provided.


• PRISMA Flow Diagram: While not the criteria itself, this diagram can give you an overview of how many studies were identified and screened, and where exclusions happened, which implicitly reflects the criteria.

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Phase 2: Check for Pre-registration or Protocol Publication

Many systematic reviews are pre-registered or have a published protocol, which often contains more detail than the final published paper.

• PROSPERO (International Prospective Register of Systematic Reviews):


• Check the published article: Look for a PROSPERO registration number (e.g., "PROSPERO CRD42018xxxxxx") usually in the methods section or acknowledgements.


• Search PROSPERO directly: Go to www.crd.york.ac.uk/prospero/ and search by the review's title, keywords, or the lead author's name.


• What you might find: PROSPERO registrations require detailed information on eligibility criteria, planned search strategies for each database, data extraction plans, and risk of bias assessment methods. This can be an incredibly rich source.


• Other Registries/Protocol Journals:


• OSF Registries: (osf.io/registries) Some reviews might be registered here.


• Cochrane Library / Joanna Briggs Institute (JBI): If the original review was conducted by a Cochrane or JBI group, their protocols are typically published in the Cochrane Database of Systematic Reviews or the JBI Evidence Synthesis.


• Specific Protocol Journals: Some journals specifically publish systematic review protocols (e.g., Systematic Reviews journal by BMC).

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Phase 3: Contact the Original Authors

If after Phases 1 and 2 you still cannot find the complete information, contacting the original authors is a professional and often fruitful approach.

• Identify the Corresponding Author: Their email address is usually provided in the published article.


• Draft a Polite and Specific Email:


• Introduce yourself: Briefly state your affiliation and purpose.


• State your intention: Clearly mention you are planning to update their systematic review. Acknowledge their work.


• Be specific about what you need:


• "We are having difficulty locating the full search strategy as run in [specific database, e.g., Embase or Web of Science]."


• "Could you please share the complete search strategy files (e.g., text files or screenshots) for each database used in your review?"


• "Are there any additional details regarding your eligibility criteria that were not fully captured in the published article or PROSPERO registration?"


• Offer collaboration (optional but can be helpful): You might suggest acknowledging their contribution in your update or even offering them a chance to be involved if appropriate and they are interested.


• Thank them in advance:


• Example Email Snippet:

> Dear Dr. [Author's Last Name],
>
> My name is [Your Name] from [Your Institution]. I am a researcher in [Your Field] and I am planning to update your excellent systematic review, "[Review Title]," published in [Journal Name] (DOI: [DOI]).
>
> To ensure consistency and rigor in our update, we are trying to obtain the complete, line-by-line search strategies as run in each of the databases you utilized (e.g., PubMed, Embase, Web of Science). While we found some details in the article's methods section and supplementary materials, we are keen to replicate the exact searches for all platforms.
>
> Would you be able to share these full search strategies with us, or point us to where we might find them? Any guidance on specific eligibility criteria nuances not fully captured in the main text would also be greatly appreciated.
>
> Thank you very much for your time and assistance.
>
> Sincerely,
> [Your Name]
> [Your Affiliation]
> [Your Contact Info]

• Be Patient: Authors are busy. Give them a week or two to respond. If you don't hear back, a single polite follow-up email is acceptable.

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Phase 4: Consult a Research Librarian (Highly Recommended!)

Research librarians, especially those specializing in systematic reviews or your specific field, are experts in database searching and locating information.

• How they can help:


• They can often help you navigate complex journal websites or institutional repositories.


• They might have access to specialized databases or resources that you don't.


• They can review the published methods and give you advice on where the full strategies might be hidden, or how to reconstruct them if they are truly unavailable.


• They can offer invaluable advice for developing your updated search strategy.

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What if You Still Can't Get the Full Strategy? (Worst Case Scenario)

If, after all these steps, you cannot obtain the complete search strategies for all databases, you will need to:

• Clearly document your attempts: State in your updated review that you made every effort to obtain the original strategies and outline the steps you took.


• Reconstruct the strategy: Based on the keywords and partial strategies provided in the main paper, and potentially the eligibility criteria, you will need to infer and reconstruct a search strategy as closely as possible. This is more challenging but sometimes necessary. You'll need to justify your reconstruction.


• Acknowledge limitations: Be transparent about the fact that you had to reconstruct part of the original methodology.

By following this systematic approach, you significantly increase your chances of obtaining the original search strategies and eligibility criteria, setting a strong foundation for your updated systematic review. Good luck!