Simpson’s Paradox is suppression, but Lord’s Paradox is neither: clarification of and correction to Tu, Gunnell, and Gilthorpe (2008)

Table 1 Associations between treatment and status.

	Untreated	Treated
Association between treatment and status, disregarding sex
Alive	6	20
Dead	6	20
Total	12	40
Probability dead	.50	.50	No association

	Male		Female
	Untreated	Treated	Untreated	Treated
Association between treatment and status for each sex
Alive	4	8	2	12
Dead	3	5	3	15
Total	7	13	5	27
Probability dead	.43	.38	.60	.56	Negative association for both male and female

Status coded 0 = alive, 1 = dead; treatment coded 0 = untreated, 1 = treated; sex coded 0 = male, 1 = female