提供: Vaccipedia | Resources for Vaccines, Tropical medicine and Travel medicine
ナビゲーションに移動
検索に移動
Navigation Menu
|
|
General issues of Vaccine
|
|
General issues of Tropical med.
|
|
General issues of Travel med.
|
|
Trematode (fluke, distoma)
|
|
Three mechanisms (assumptions) of data missing
Mechanisms (assumptions) of data missing
|
Description
|
[*Example] A cohort study in which participants report their body weight every week to research center
|
Missing not at random MNAR
|
Missing depends on observed data themselves
|
|
Missing at randam MAR
|
- Missing does not depend on observed data but may depend on unobserved data
- Missing can be explained
|
Female participants less likely report their body weights than male participants:
- Data of female participants are more likely missed not because of data (body weights) themselves but because female tend to be reluctant to report their body weights
- In other words, the variable of body weight itself does not affect the missing but another variable sex affects the missing of values in the variable body weight
|
Missing completely at random MCAR
|
- Missing does not depend on observed data nor on unobserved data
- Missing occurs purely at random independely from any observed and unobserved data
|
A participant moves to outside cohort area because of family affair which has nothing to do with the study and is lost to follow up:
- Data after the move are missed not because of data (body weights) themselves nor because of the participant's unobserved (unmeasured) characteristic
|