New law may be having some effect on publication bias.
Tuma
Rabiya S
RS
D002986:Clinical Trials as Topic / Q000379:methods; D006801:Humans; D055811:Journal Impact Factor; D018156:Journalism, Medical; D010506:Periodicals as Topic / Q000331:legislation & jurisprudence* / Q000592:standards; D017594:Publication Bias / Q000331:legislation & jurisprudence; D016032:Randomized Controlled Trials as Topic / Q000379:methods; D012042:Registries; D012107:Research Design; D006113:United Kingdom; D014481:United States