Intended for healthcare professionals

Endgames Statistical Question

What is a non-randomised controlled trial?

BMJ 2014; 348 doi: (Published 20 June 2014) Cite this as: BMJ 2014;348:g4115
  1. Philip Sedgwick, reader in medical statistics and medical education
  1. 1Institute of Medical and Biomedical Education, St George’s, University of London, London, UK
  1. p.sedgwick{at}

Researchers investigated whether a low cost public campaign by local health authorities reduced antibiotic prescribing for outpatients. A non-randomised controlled trial study design was used. The intervention was multifaceted and included posters, brochures, and advertisements on local media, plus a newsletter on local antibiotic resistance targeted at doctors and pharmacists. The campaign focused primarily on the prescription of antibiotics for upper respiratory tract infections. The trial was based in Emilia-Romagna in northern Italy. The provinces of Modena and Parma (about 1 150 000 residents) were chosen for implementation of the intervention between November 2011 and February 2012. The provinces where the campaign was not implemented, with no information provided to doctors and pharmacists, formed the control group (about 3 250 000 residents). The primary outcome was the change in prescribing rates of antibiotics for outpatients over five months.1

The researchers reported that a low cost community based public campaign targeted at residents, combined with a newsletter on local antibiotic resistance for doctors and pharmacists, was associated with a significantly decreased total rate of antibiotic prescribing. However, the campaign did not affect the participants’ knowledge and attitudes about antibiotic resistance.

Which of the following statements, if any, are true?

  • a) The choice of provinces …

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