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. 2017 Sep 26;19(4):407–425. doi: 10.1093/biostatistics/kxx045

Table 1.

Assumptions and general guidelines for making partly conditional inference

Method Assumption under which method is valid Guidelines for use
IPWInline graphic u-MAR (1) u-MAR is equivalent to mortal-cohort dDTIC and missingness-independent death (2) u-MAR is the discrete death-time version of MAR in Kurland and Heagerty (2005)
  • Model probability of dropout at visit Inline graphic for those who survived up to visit Inline graphic

  • Do not include Inline graphic in dropout models

  • Appropriate when longitudinal and survival processes depend on one another, and survival process does not depend on dropout process

  • u-MAR assumption can be tested if survival is known up to the end of study

IPWInline graphic p-MAR Note: p-MAR is a weaker assumption than u-MAR
  • Model probability of dropout at visit Inline graphic for those who survived up to and including visit Inline graphic, Inline graphic

IPWInline graphic f-MAR (1) f-MAR is a weaker assumption than u-MAR (2) f-MAR is the discrete death-time version of MAR-S in Kurland and Heagerty (2005)
  • For visit each Inline graphic, model the probability of dropout at visit Inline graphic for those who die between visits Inline graphic and Inline graphic (i.e. whose Inline graphic)

  • Include Inline graphic in dropout models

MIInline graphic/LIInline graphic mortal-cohort dDTIC and independent death
  • Do not include Inline graphic in the imputation models

  • Delete imputed post-death outcomes before analysis

  • Appropriate when survival and dropout processes depend on one another, and survival process does not depend on missing outcome process

MIInline graphic/LIInline graphic f-MAR
  • Include Inline graphic in imputation models

  • Delete imputed post-death outcomes before analysis

AIPWInline graphic either i) u-MAR or ii) p-MAR, f-MAR and independent death
  • Do not include Inline graphic in dropout and imputation models

  • Delete imputed post-death outcomes

  • At least as efficient as IPWInline graphic if dropout and imputation models are correctly specified and survival process does not depend on longitudinal process (death still truncates longitudinal and dropout processes)

AIPWInline graphic f-MAR
  • Valid as long as either dropout or imputation models are correctly specified

  • Include Inline graphic in dropout and imputation models

  • Delete imputed post-death outcomes

  • At least as efficient as IPWInline graphic if dropout and imputation models are correctly specified and data are f-MAR