Data extraction methods: an analysis of internal reporting discrepancies in single manuscripts and practical advice

Area of Science:

• Medical research methodology
• Evidence synthesis

Background:

• Data extraction is vital for evidence syntheses like systematic reviews (SRs).
• Reporting discrepancies, where statements conflict, can occur within single publications.
• These internal inconsistencies pose methodological challenges for SR authors.

Purpose of the Study:

• To highlight examples of internal reporting discrepancies within single study sources.
• To increase awareness among SR authors regarding potential methodological issues.
• To provide guidance on managing and reporting such discrepancies.

Main Methods:

• The study describes and exemplifies internal reporting discrepancies found within a single source.
• It emphasizes the importance of cross-referencing information within a study.
• Independent data extraction by two reviewers is recommended to detect discrepancies.

Main Results:

• Internal reporting discrepancies can exist within a single manuscript.
• These discrepancies may arise between different sections of the same publication.
• Awareness and detection methods are key to addressing these issues.

Conclusions:

• Authors of SRs and overviews of SRs must verify information consistency within studies.
• Independent data extraction enhances the identification of discrepancies.
• Guidance is provided for handling and reporting identified discordances.