差分

!style="width:7em" rowspan="2"|!Descriptionstyle="witdh:4em" rowspan="2"|Abbr.!colspan="2"|Missing depends on/<br>Missing occurs because of!rowspan="2"|[*Example]<br>A cohort study in which participants self report their body weight every week to research center for 52 weeks in totalvia special app installed on their smartphones. Demographic variables are also collected.

!style="width:7em"|missing (unobserved) value itself!style="width:7em"|other observed variable(s)|-!Missing not at random!MNAR|style="text-align:center"|<brbig>YES</big>MNAR|*Missing depends on observed datastyle="text-align:center"|&mdash;

*Some participants '''intentionally deny denied to report higher body weights they dondidn't like''' and only report reported lower body weights they likeaccepted*Researchers have no information why they denied to report body weights in several weeks**Data of those participants are missed Missing occurred '''because of the missing values in the variable ''body weight'' themselves'''**Researchers cannot explain/predict the missing mechanism from other observed (reported) body weights or other variables

!Missing at randam!MAR|style="text-align:center"|<big>NO<br/big>MAR|*Missing does not depend on '''unobserved data''', but may depend on '''observed data'''*The cause of missing can be explained bystyle="text-align:center"|<big>YES</big>

*'''15% of female participants deny denied to report ''' their body weights after the agreement participation '''regardless of measured body weights''', but only 1% of male deny denied to report:**Data of Researchers can identify that female participants are more likely missed not because of data (body weights) themselves but because female are more likely reluctant denied to report their body weightsthan male**In other words, values in the variable Missing occurred NOT because of body weights themselves but ''body weight'' themselves do not affect the missing but because of another variable ''sex'' affects the '''**Missing mechanism is at random, i.e., free from missing of values in the only inside each participant, but NOT at random, i.e., NOT free from variable ''body weightsex''

!Missing completely at random!MCAR|style="text-align:center"|<big>NO<br/big>MCAR|*Missing does NOT depend on '''observed data''' NOR on '''unobserved data'''*Missing occurs purely at random independely from any observed and unobserved datastyle="text-align:center"|<big>NO</big>

*A participant moves '''moved to outside cohort area ''' because of family affair which has nothing to do with the study and is was lost to follow up at *A participant '''failed to report body weights because of malfunction of the 10th week:app'''**Data after the move are missed not Missing occurred NOT because of data (body weights) themselvesNOR other variables**Missing mechanism is completely at random, i.e., nor because completely free from both of the participant's missing (unobserved (unmeasured) characteristic related to the studyvalues and observed values in body weight or in other variables