Terminology summary
Pathway-preference: A ligand’s differential activity across pathways (e.g. pathway ΔLog(Emax/EC50) or ΔLog(Emax/EC50) values), not comparing to a reference ligand. As no reference ligand is used, the comparison must be made ideally using the same or otherwise near-identical systems and assays.

Report underlying quantitative data of bias factors

Recommendation 8: We recommend authors to tabulate the underlying quantitative values of the pharmacological parameters used to calculate a bias factor (templates are provided in Tables 3-4). Reporting these values will improve clarity, increase transparency and future-proof cross-study comparisons. It also allows databases to calculate and present multiple models of bias or to change the choice of reference ligand to facilitate comparison across studies. Furthermore, we recommend always reporting slope factors of the concentration-response curves. This information is critical especially when ΔΔLog(Emax/EC50) is used to assess bias, as slope factors deviating from 1 indicate the extent to which system bias (rather than ligand bias) contributes to the calculated bias factors.

Bias measured at the level of GPCR-binding transducers