Table 1.

Examples of reference‐based and external‐information‐controlled multiple‐imputation methods

Name	Description
Reference‐based controlled multiple‐imputation methods
Jump to reference	Imputes assuming that following dropout a patient's mean profile follows that observed in the reference arm Pre‐dropout means come from the randomized arm
Copy increments in reference	Forms post‐dropout means by copying increments in the reference arm Pre‐dropout means come from the randomized arm
Last mean carried forward	Forms post‐dropout means by carrying forward the randomized arm mean at dropout
Copy reference	The conditional profile given the history is copied from the reference group, i.e. imputes as if randomized to the reference arm pre‐ and post‐dropout means come from the reference arm
External‐information‐controlled multiple‐imputation methods
δ‐method	Impute under randomized arm MAR and subtract or add by fixed δ