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Table 2 Study design – Was clustering non-ignorable?

From: Clustering of continuous and binary outcomes at the general practice level in individually randomised studies in primary care - a review of 10 years of primary care trials

Study IDStudy topicCondition 1: ICC non-zeroCondition 2: Correlation of patient assignments within cluster non-zero, ReasonBoth conditions met for non-ignorable clustering
1GRACE trial – antibiotics for lower respiratory tract infection [15]YY, Block randomsiationY
2Internet Doctor – self management of respiratory tract infections [16]YN, Simple randomisationN
3Internet based vestibular rehabilitation for dizziness [17]YY, randomisation stratified on patient factorsY
4PIPS – ibuprofen, paracetamol and steam for respiratory tract infections [18]YN, Simple randomsiationN
5POWER plus – management of obesity [19]YY, randomisation stratified on patient factorsY
6PRIMIT – handwashing to modify respiratory tract infection transmission [20]YN, Simple randomsiationN
7SNIFS – Steam inhalation & nasal irrigation for sinus symptoms [21]YN, Simple randomsiationN
8TASTE – Probiotics and chewing gum for sore throat [22]YN, Simple randomsiationN
9AIRS – Autoinflation for children with otitis media [23]YN, Simple randomsiationY
10GNOME – Topical intranasal corticosteroids in children with otitis media [24]NY, Block randomsiationN
11ATEAM – Alexander technique, exercise, massage for chronic back pain [25]YY, Block randomsiationY
12ASCOT – Antibiotics and topical nasal steroid for sinusitis [26]YY, Block randomsiationY
13Antibiotic prescribing for conjunctivitis [27]NY, Block randomsiationN
14Leaflet and antibiotic prescribing for lower respiratory tract infection [28]YY, Block randomsiationY
15PIPO – probiotics for prevention of otitis media in childrenbYN, Simple randomsiationN
16THREAD – SSRI for depression [29]NY, randomisation blocked and stratified on patient factorsN
17MIBS – management of irritable bowel syndrome [30]YY, randomisation blocked and stratified on patient factorsY
  1. bUnpublished, private correspondence