Making protocols available with the article improved evaluation of selective outcome reporting.

Area of Science:

• Clinical Trials Methodology
• Research Integrity
• Publication Bias

Background:

• Selective outcome reporting (SOR) is a threat to the validity of clinical trial results.
• Assessing SOR is crucial for interpreting research findings accurately.
• Trial registration and protocols are key documents for evaluating reporting consistency.

Purpose of the Study:

• To compare primary outcomes across publications, protocols, and registries.
• To evaluate the added value of protocols in detecting SOR compared to registration alone.

Main Methods:

• Analysis of randomized controlled trials (RCTs) published in 2015-2016 in top medical journals.
• Extraction of primary outcomes from publications, registries, and available protocols.
• Assessment of SOR by comparing reported outcomes, considering trial registration and protocols.

Main Results:

• SOR was suspected in 28.1% of RCTs when comparing publications to registration alone.
• Inclusion of protocols changed the SOR assessment for 13.9% of RCTs.
• Protocols identified additional cases of suspected SOR and clarified unclear assessments.

Conclusions:

• Availability of protocols enhances the precision of SOR evaluation compared to using trial registration alone.
• Protocols provide a more comprehensive basis for assessing research integrity and reporting consistency.