# Randomization of Intervention-control Pairs

This function provides random allocation into intervention or control arms of a trial for a paired/matched experimental design. Each subject will experience both intervention and control treatment at some stage during the trial, the paired randomization determines the treatment order.

Randomization reduces opportunities for bias and confounding in experimental designs, and leads to treatment groups which are random samples of the population sampled, thus helping to meet assumptions of subsequent statistical analysis (Bland, 2000). A particular bias in this design might be intervention having some carry-over effect on control treatment.

Example: randomization of 50 patients into treatment (intervention) and placebo (control) arms of a trial of a new drug. This would give 50 pairs of INTERVENTION - CONTROL or CONTROL - INTERVENTION. If this was a randomized crossover study then you would give drug first if the order was INTERVENTION - CONTROL and you would give placebo first if the order was CONTROL - INTERVENTION:

Randomized intervention-control pairs

Randomized with seed: 10, balanced allocation:

 1 Intervention - Control 2 Control - Intervention 3 Intervention - Control 4 Intervention - Control 5 Control - Intervention 6 Control - Intervention 7 Intervention - Control 8 Control - Intervention 9 Intervention - Control 10 Control - Intervention 11 Intervention - Control 12 Control - Intervention 13 Control - Intervention 14 Intervention - Control 15 Intervention - Control 16 Intervention - Control 17 Control - Intervention 18 Control - Intervention 19 Intervention - Control 20 Control - Intervention 21 Intervention - Control 22 Control - Intervention 23 Control - Intervention 24 Intervention - Control 25 Control - Intervention 26 Control - Intervention 27 Control - Intervention 28 Intervention - Control 29 Intervention - Control 30 Intervention - Control 31 Intervention - Control 32 Intervention - Control 33 Intervention - Control 34 Control - Intervention 35 Control - Intervention 36 Intervention - Control 37 Intervention - Control 38 Control - Intervention 39 Control - Intervention 40 Control - Intervention 41 Control - Intervention 42 Intervention - Control 43 Control - Intervention 44 Control - Intervention 45 Intervention - Control 46 Intervention - Control 47 Control - Intervention 48 Control - Intervention 49 Intervention - Control 50 Intervention - Control

Technical validation

Robust (pseudo-)random number generation is used, see random number generation.