. 2017 Jun;107(6):907–915. doi: 10.2105/AJPH.2017.303706

TABLE 3—

Characteristics of the Parallel-Arm Group Randomized Trial and of Alternative Group Designs

	One-Stage Randomization			Type of Follow-Up Possible
Design (Abbreviation)	By Group	By Individual	Two-Stage Randomization	Cross-Sectional	Cohort
Parallel-arm group-randomized trial (GRT)	✓	. . .	. . .	✓	✓
Stepped-wedge group-randomized trial (SW-GRT)	✓	. . .	. . .	✓	✓
Network-randomized group-randomized trial (NR-GRT)	✓	. . .	. . .	. . .	✓^a
Pseudocluster randomized trial (PCRT)	. . .	. . .	✓	. . .	✓^b
Individually randomized group-treatment trial (IRGT trial)	. . .	✓	. . .	. . .	✓^c

^{^a}

In the NR-GRT, the index case and its network are usually defined at baseline, and therefore the design is expected to use a cohort design and not allow a cross-sectional design.

^{^b}

In the PCRT, because randomization is undertaken in 2 stages with individuals randomized to intervention or control in the second stage, the design requires that a cohort of individuals be enrolled at study baseline to be followed over time.

^{^c}

In the IRGT trial, individual randomization is performed, and therefore, like the pseudocluster randomized trial, a cohort of individuals is enrolled and followed over time.