Table 1.

Comparison of abortion incidence estimation methodologies

	Expected direction of bias	Expected magnitude of bias	Relative precision	Ability to capture self-induced abortions known only to woman	Potential to yield contextual information	Key data sources
Methods reviewed in this paper
Abortion incidence complications method	Unknown	Unknown	Moderate	Only if led to PAC	From PAC facilities and knowledgeable informants	Health facility survey, survey of knowledgeable informants
Direct questioning	Underestimation	Very high	Very low	Yes	From women who admit to having an abortion	Population-based survey of women
List experiment	Underestimation	Low	Low	Yes	No	Population-based survey of women
Confidante method	Underestimation	Moderate	High	No	Limited	Population-based survey of women
CM with visibility factor	Unknown	Low	High	Yes	Limited	Population-based survey of women
Modified AICM	Unknown	Unknown	Low /moderate	Yes	From PAC facilities and women who admit their abortions	Health facility survey, population-based survey of women
Other methods
Preceding birth technique	Underestimation	High	Low	Yes	From women who admit to having an abortion	Suvey of antenational clinic patients
Sealed envelope	Underestimation	Inconsistent	Low	Yes	No	Population-based survey of women
Randomized response technique	Unknown	Unknown	Low	Yes	No	Population-based survey of women
Residual method	Unknown	Unknown	Very low	Yes	No	Secondary data
Best friend approach	Underestimation	Low/moderate	Moderate	No	Limited	Population-based survey of women
Sealed envelope	Underestimation	Moderate	Very high	No	Limited	Population-based survey of women
Network scale-up	Unknown	Unknown	Very high	Yes	No	Population-based survey of women