Table 2.

Comparison of trial that was highly explanatory in attitude with trial that was highly pragmatic

	Highly explanatory attitude (NASCET7)	Highly pragmatic attitude (Thomas et al8)
Question	Among patients with symptomatic 70-99% stenosis of carotid artery can carotid endarterectomy plus best medical therapy reduce outcomes of major stroke or death over next two years compared with best medical therapy alone?	Does a short course of acupuncture delivered by a qualified acupuncturist reduce pain in patients with persistent non-specific low-back pain?
Setting	Volunteer academic and specialist hospitals with multidisciplinary neurological-neurosurgical teams and high procedure volumes with low mortality in US and Canada	General practice and private acupuncture clinics in UK
Participants	Symptomatic patients stratified for carotid stenosis severity, with primary interest in severe carotid stenosis (high risk) group, who were thought to be most likely to respond to endarterectomy. Exclusions included mental incompetence and another illness likely to cause death within 5 years. Patients also were temporarily ineligible if they had any of seven transient medical conditions (eg, uncontrolled hypertension or diabetes)	Anyone aged 18-65 with non-specific low back pain of 4-52 weeks’ duration who were judged to be suitable by their general practitioner. There were some exclusion criteria, eg those with spinal disease
Intervention	Endarterectomy had to be carried out (rather than stenting or some other operation), but the surgeon was given leeway in how it was performed. Surgeons had to be approved by an expert panel, and were restricted to those who had performed at least 50 carotid endarterectomies in the past 24 months with a postoperative complication rate (stroke or death within 30 days) of less than 6%. Centre compliance with the study protocol was monitored, with the chief investigator visiting in the case of deficiencies	Acupuncturists determined the content and number of treatments according to patients’ needs
Outcomes	The primary outcome was time to ipsilateral stroke, the outcome most likely to be affected by carotid endarterectomy. Secondary outcomes: all strokes, major strokes, and mortality	Primary outcome was bodily pain as measured by SF-36. Secondary outcomes included use of pain killers and patient satisfaction
Relevance to practice	Indirect—patients and clinicians are highly selected and it isn’t clear how widely applicable the results are	Direct—general practitioners and patients can immediately use the trial results in their decision making