Which aspect of a systematic review's methodology helps reduce selection bias when identifying studies?

Which aspect of a systematic review's methodology helps reduce selection bias when identifying studies?

• A. Conducting a comprehensive search and clear study selection process
• B. Limiting search to English-language studies
• C. Excluding unpublished studies
• D. Not performing study screening

Answer: (A)

The main idea is that reducing selection bias in a systematic review comes from casting a wide, transparent net for studies and applying the selection criteria consistently. This means using a comprehensive search across multiple sources (databases, trial registries, grey literature) and following a preplanned, clearly defined set of inclusion and exclusion criteria. Having two or more reviewers independently screen studies and resolve disagreements with a predefined method adds checks to prevent individual preferences from shaping what gets included. Documenting the process and showing how studies were identified and screened (for example, with a flow diagram) provides transparency so others can assess the thoroughness of the search and the consistency of study selection. Limiting to English-language studies, excluding unpublished work, or skipping screening would introduce biases or simply fail to identify relevant evidence, which is why they are not appropriate strategies for reducing selection bias.

The main idea is that reducing selection bias in a systematic review comes from casting a wide, transparent net for studies and applying the selection criteria consistently. This means using a comprehensive search across multiple sources (databases, trial registries, grey literature) and following a preplanned, clearly defined set of inclusion and exclusion criteria. Having two or more reviewers independently screen studies and resolve disagreements with a predefined method adds checks to prevent individual preferences from shaping what gets included. Documenting the process and showing how studies were identified and screened (for example, with a flow diagram) provides transparency so others can assess the thoroughness of the search and the consistency of study selection. Limiting to English-language studies, excluding unpublished work, or skipping screening would introduce biases or simply fail to identify relevant evidence, which is why they are not appropriate strategies for reducing selection bias.