Transport is an important determinant of health, and the health impact of transport interventions requires robust evaluation. Systematic reviews provide a rigorous tool for locating, appraising, and synthesizing evaluative evidence. Some systematic reviews use meta-analysis techniques to synthesize data, but other systematic reviews do not. This paper addresses some methodological and practical issues associated with conducting systematic reviews on the health impact of transport interventions. By using as case studies recently conducted reviews on topics such as the health impact of new roads and the effectiveness of interventions in promoting modal shift, the paper outlines many of the challenges faced by systematic reviewers in this field. It then describes some research synthesis techniques available to systematic reviewers and discusses some of the strengths and weaknesses of these techniques. Systematic literature reviews on the health impact of specific transport interventions can be used to inform decision making. However, reviews of such complex interventions require an innovative approach to the methodologies of systematic reviews and research synthesis.
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References
1.
ChalmersI.Trying to Do More Good Than Harm in Policy and Practice: The Role of Rigorous, Transparent, and Up to Date Evaluations. Annals of the American Academy of Political and Social Science, Vol. 589, 2003, pp. 22–40.
2.
WanlessD.Securing Good Health for the Whole Population: Final Report.HM Treasury, London, 2004.
3.
MackenbachJ. P., BakkerB. B., and EU Network on Interventions and Policies to Reduce Inequalities in Health. Tackling Socioeconomic Inequalities in Health: Analysis of European Experiences. Lancet, Vol. 362, 2003, pp. 1409–1414.
4.
AchesonD.Independent Inquiry into Inequalities in Health Report.The Stationery Office, London, 1998.
5.
PetticrewM.Systematic Reviews from Astronomy to Zoology: Myths and Misconceptions. British Medical Journal, Vol. 322, 2000, pp. 98–101.
6.
CooperH.Integrating Research: A Guide for Literature Reviews.Sage, London, 1989.
Centre for Reviews and Dissemination.Undertaking Systematic Reviews of Research on Effectiveness: CRD's Guidance for Those Carrying Out or Commissioning Reviews. CRD Report 4, 2d ed. University of York.2001. www.york.ac.uk/inst/crd. Accessed March 23, 2005.
9.
AldersonP., GreenS., and HigginsJ., eds. Cochrane Reviewers’ Handbook 4.2.2: The Cochrane Library, Issue 1. John Wiley and Sons, Chichester, England, 2004.
10.
ReesJ.Two Cultures. Journal of the American Academy of Dermatology, Vol. 46, 2002, p. 314.
11.
Charter on Transport, Environment and Health.World Health Organization, Copenhagen, Denmark, 1999.
12.
World Disasters Report.International Federation of Red Cross and Red Crescent Societies, Geneva, Switzerland, 1998.
13.
EganM., PetticrewM., OgilvieD., and HamiltonV.New Roads and Human Health: A Systematic Review. American Journal of Public Health, Vol. 93, No. 9, 2003, pp. 1463–1471.
14.
EllawayA., MacintyreS., HiscockR., and KearnsA.In the Driving Seat: Psychosocial Benefits from Private Motor Vehicle Transport Compared to Public Transport. Transportation Research Part F, Vol. 6, No. 3, 2003, pp. 217–231.
15.
McCarthyM.Transport and Health. In Social Determinants of Health (MarmotM. and WilkinsonR., eds.), Oxford University Press, Oxford, England, 1999, pp. 132–154.
16.
MorrisJ.Exercise in the Prevention of Coronary Heart Disease: Today's Best Buy in Public Health. Medicine and Science in Sports and Exercise, Vol. 26, 1996, pp. 807–814.
17.
MorrisonD., PetticrewM., and ThomsonH.What Are the Most Effective Ways of Improving Population Health Through Transport Interventions? Evidence from Systematic Reviews. Journal of Epidemiology and Community Health, Vol. 57, 2003, pp. 327–333.
18.
OgilvieD., EganM., HamiltonV., and PetticrewM.Promoting Walking and Cycling as an Alternative to Using Cars: Systematic Review. British Medical Journal, Vol. 329, 2004, pp. 763–766.
19.
WentzR., RobertsI., BunnF., EdwardsP., KwanI., and LefebvreC.Identifying Controlled Evaluation Studies of Road Safety Interventions: Searching for Needles in a Haystack. Journal of Safety Research, Vol. 32, 2001, pp. 267–276.
20.
WeissbrodtG.Auswirkungen von Ortsumgehungen auf die Verkehrssicherheit. Heft 48, Unfall- und Sicherheitsforschung Strassenverkehr.Bergisch-Gladbach, Bundesanstalt für Strassenwesen, 1984.
21.
ElvikR.The Importance of Confounding in Observational Before-and-After Studies of Road Safety Measures. Proc., 13th ICTCT Workshop. Corfu: International Cooperation on Theories and Concepts in Traffic Safety, 2000, pp. 105–117.
22.
HauerE.Observational Before-After Studies in Road Safety: Estimating the Effect of Highway and Traffic Engineering Measures on Road Safety.Pergamon, Oxford, England, 1997.
23.
RamsayC., MatoweL., GrilliR., GrimshawJ., and ThomasE.Interrupted Time Series Designs in Health Technology Assessment: Lessons from Two Systematic Reviews of Behavior Change Strategies. International Journal of Technology Assessment in Health Care, Vol. 19, No. 4, 2003, pp. 613–623.
24.
SpencerL., RitchieJ., LewisJ., and DillonL.Quality in Qualitative Evaluation: A Framework for Assessing Research Evidence.National Centre for Social Research, U.K. Government Chief Researchers Office, London, 2003.
25.
CooperH., and HedgesL. V., eds. The Handbook of Research Synthesis.Russell Sage Foundation, New York, 1994.
26.
Davey SmithG., and EggerM.Meta-Analysis: Unresolved Issues and Future Developments. British Medical Journal, Vol. 316, 1998, pp. 221–225.
27.
EggerM., SchneiderM., and Davey SmithG.Spurious Precision? Meta-Analysis of Observational Studies. British Medical Journal, Vol. 316, 1998, pp. 140–144.
28.
LightR., and SmithP.Accumulating Evidence: Procedures for Resolving Contradictions Among Different Research Studies. Harvard Educational Review, Vol. 41, 1971, pp. 429–471.
29.
ElvikR., AmundsenF. H., and HofsetF.Road Safety Effects of Bypasses. In Transportation Research Record: Journal of the Transportation Research Board, No. 1758, TRB, National Research Council, Washington, D.C., 2001, pp. 13–20.
30.
AmundsenA. H., and ElvikR.Effects on Road Safety of New Urban Arterial Roads. Accident, Analysis and Prevention, Vol. 36, No. 1, 2004, pp. 115–123.
31.
OxmanA., and GuyattG.Validation of an Index of the Quality of Review Articles. Journal of Clinical Epidemiology, Vol. 44, 1991, pp. 1271–1278.
32.
AldersonP., and RobertsI.Should Journals Publish Systematic Reviews That Find No Evidence to Guide Practice? Examples from Injury Research. British Medical Journal, Vol. 320, 2000, pp. 376–377.
33.
PetticrewM.Why Certain Systematic Reviews Reach Uncertain Conclusions. British Medical Journal, Vol. 326, 2003, pp. 756–758.
34.
U.K. Department for Education and Employment.Blunkett Rejects Anti-Intellectualism and Welcomes Sound Ideas. DfEE News, 43/00, 2000.
