Clinical study protocol on electronic cigarettes and nicotine pouches for smoking cessation in Pakistan: a randomized controlled trial

Table 2 The double difference design to measure treatment effect

	Baseline value of indicator	Follow-up value of indicator	Difference over time
Beneficiary group (intervention)	a	c	c–a
Non-beneficiary	B	d	d–b
(comparison)	B	d	d–b
Difference over group	a–b	c–d	DID (treatment effect) = (d–b)–(c–a)
			or
			(a–b)–(c–d)

Depending upon the measurement scale of each indicator, the cells (a, b, c, and d) in the table can be primary and secondary outcomes indicators

ISSN: 1745-6215