Intended for healthcare professionals

Education And Debate

Evaluating the health effects of social interventions

BMJ 2004; 328 doi: (Published 29 January 2004) Cite this as: BMJ 2004;328:282
  1. Hilary Thomson, higher scientific officer (,
  2. Robert Hoskins, lecturer2,
  3. Mark Petticrew, associate director1,
  4. Neil Craig, lecturer3,
  5. Tony Quinn, project manager4,
  6. Grace Lindsay, lecturer5,
  7. David Ogilvie, specialist registrar in public health medicine1
  1. 1MRC Social and Public Health Sciences Unit, Glasgow, G12 8RZ
  2. 2Nursing and Midwifery School, University of Glasgow, Glasgow
  3. 3Public Health and Health Policy, Division of Community Based Sciences, University of Glasgow
  4. 4Easterhouse Money Advice Centre, Easterhouse, Glasgow
  5. 5School of Nursing, Midwifery and Community Health, Glasgow Caledonian University, Glasgow
  1. Correspondence to: Hilary Thomson
  • Accepted 25 November 2003

Is no evidence better than any evidence when controlled studies are unethical?

Rigorous evidence on the health effects of social interventions is scarce1 2 despite calls for more evidence from randomised studies.3 One reason for the lack of such experimental research on social interventions may be the perception among researchers, policymakers, and others that randomised designs belong to the biomedical world and that their application to social interventions is both unethical and simplistic.4 Applying experimental designs to social interventions may be problematic but is not always impossible and is a desirable alternative to uncontrolled experimentation.3 However, even when randomised designs have been used to evaluate social interventions, opportunities to incorporate health measures have often been missed.5 For example, income supplementation is thought to be a key part of reducing health inequalities,6 but rigorous evidence to support this is lacking because most randomised controlled trials of income supplementation have not included health measures.5 Current moves to increase uptake of benefits offer new opportunities to establish the effects of income supplements on health. In attempting to design such a study, however, we found that randomised or other controlled trials were difficult to justify ethically, and our eventual design was rejected by funders.

Box 1 Attendance allowance

  • Attendance allowance is payable to people aged 65 or older who need frequent help or supervision and whose need has existed for at least six months

  • The rate payable depends on whether they need help at home or only when going out and whether they need help during the day or the evening, or both

Aims of study

A pilot study carried out by one of us (RH) showed substantial health gains among elderly people after receipt of attendance allowance. We therefore decided to pursue a full scale study of the health effects of income supplementation. …

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