How Much Participant Outcome Data Is Missing from Sight: Findings from a Cohort of Trials Submitted to a German Research Ethics Committee.

ABSTRACT:

Background

Study publication bias and outcome reporting bias have been recognised as two threats to the validity of systematic reviews. The purpose of this research was to estimate the proportion of missing participant outcome data from randomised controlled trials (RCTs) due to lack of publication of whole studies and due to outcome data missing within study publications.

Methods and findings

Data were extracted from protocols of clinical research projects submitted to the research ethics committee of the University of Freiburg (Germany) between 2000 and 2002 and associated fully published articles. The total amount of published and unpublished outcome data from all trial participants was calculated for each trial and the overall proportion of missing data from both unpubli

SUBMITTER: Kirkham JJ 

PROVIDER: S-EPMC4912080 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature