Skip to main content
. 2017 Jun 12;12(6):e0179536. doi: 10.1371/journal.pone.0179536

Fig 4. Begg’s funnel plot for assessment of potential publication bias in studies investigating the correlation between programmed cell death ligand 1 (PD-L1) expression and the overall survival of head and neck cancer patients.

Fig 4

No evidence of publication bias was observed, as indicated by a symmetric funnel plot (Begg’s P = 0.373). HR, hazard ratio.