- D1 (Domain 1): Bias due to confounding. D2 (Domain 2): Bias in selection of participants into the study. D3 (Domain 3): Bias in classification of interventions. D4 (Domain 4): Bias due to deviations from intended interventions. D5 (Domain 5): Bias due to missing data. D6 (Domain 6): Bias in measurement of outcomes. D7 (Domain 7): Bias in selection of the reported result