Table 2 Study design – Was clustering non-ignorable?

1

GRACE trial – antibiotics for lower respiratory tract infection [15]

Y

Y, Block randomsiation

Y

2

Internet Doctor – self management of respiratory tract infections [16]

Y

N, Simple randomisation

N

3

Internet based vestibular rehabilitation for dizziness [17]

Y

Y, randomisation stratified on patient factors

Y

4

PIPS – ibuprofen, paracetamol and steam for respiratory tract infections [18]

Y

N, Simple randomsiation

N

5

POWER plus – management of obesity [19]

Y

Y, randomisation stratified on patient factors

Y

6

PRIMIT – handwashing to modify respiratory tract infection transmission [20]

Y

N, Simple randomsiation

N

7

SNIFS – Steam inhalation & nasal irrigation for sinus symptoms [21]

Y

N, Simple randomsiation

N

8

TASTE – Probiotics and chewing gum for sore throat [22]

Y

N, Simple randomsiation

N

9

AIRS – Autoinflation for children with otitis media [23]

Y

N, Simple randomsiation

Y

10

GNOME – Topical intranasal corticosteroids in children with otitis media [24]

N

Y, Block randomsiation

N

11

ATEAM – Alexander technique, exercise, massage for chronic back pain [25]

Y

Y, Block randomsiation

Y

12

ASCOT – Antibiotics and topical nasal steroid for sinusitis [26]

Y

Y, Block randomsiation

Y

13

Antibiotic prescribing for conjunctivitis [27]

N

Y, Block randomsiation

N

14

Leaflet and antibiotic prescribing for lower respiratory tract infection [28]

Y

Y, Block randomsiation

Y

15

PIPO – probiotics for prevention of otitis media in children^b

Y

N, Simple randomsiation

N

16

THREAD – SSRI for depression [29]

N

Y, randomisation blocked and stratified on patient factors

N

17

MIBS – management of irritable bowel syndrome [30]

Y

Y, randomisation blocked and stratified on patient factors

Y