Table 2. MCAR Example: Results from a hypothetical clinical trial evaluating the effect of treatment on improvement in body fat (Outcome).

a. Results from the whole study population.
	Outcome
Treatment	Y	N
				• Risk Ratio=(30/40)/(20/40)=1.5
A	30	10	40	• SE(Ln(RR))=0.18
B	20	20	40	• 95% CI =1.05,2.15
	50	30	80	• Chi-Square=5.33 P=0.02
b. Results from completers following 30% missing data from a Missing Completely At Random Mechanism (MCAR)*.
	Outcome
Treatment	Y	N
				• Risk Ratio=(21/28)/(14/28)=1.5
A	21	7	28	• SE(Ln(RR))=0.22
B	14	14	28	• 95% CI =0.98,2.30
	35	21	56	• Chi-Square=3.73 P=0.053

*Each cell from Table 2a is multiplied by 70% to obtain 30% missing data from an MCAR mechanism in Table 2b.