Cost-effectiveness of Installing Barriers at Bridge and Cliff Sites for Suicide Prevention in Australia

by Piumee Bandara, Jane Pirkis, Angela Clapperton , Sangsoo Shin, Lay San Too, Lennart Reifels, Sandersan Onie, Andrew Page, Karl Andriessen, Karolina Krysinska, Anna Flego, Marisa Schlichthorst, Matthew J Spittal, Cathrine Mihalopoulos, Long Khanh-Dao Le

Published 1 April 2022


Installation of barriers at bridge and cliff sites has been shown to reduce suicides at these sites. But, there is often considerable resistance to installing barriers, with one key argument being cost.

Research and findings

The study examined the cost-effectiveness of installing barriers at bridge and cliff sites throughout Australia. The authors used an economic model to examine the costs, costs saved, and reductions in suicides if barriers were installed across identified bridge and cliff sites over five and 10 years.

Specific and accessible bridge and cliff sites across Australia that reported two or more suicides over a five year period were identified for analysis. A total of seven bridges and 19 cliff sites were included in the model. Inputs into the model included:

  1. Relative risk estimates of effectiveness of barriers (in terms of reductions in suicide compared with no barriers) at bridge and cliff sites
  2. Relative risk estimates of substitution to nearby sites following barrier installation
  3. Monetary value associated with preventing suicide deaths
  4. Costs of implementing and maintaining the intervention over five and 10 years.

The primary outcome was return on investment (ROI) comparing cost savings with intervention costs.

The model indicated that if barriers were installed at bridge sites, an estimated $145 million USD could be saved in prevented suicides over five years, and $270 million USD over 10 years. The estimated return on investment ratio for building barriers over 10 years at bridges was 2.4, but the results for cliff sites were not significant. The authors note that only three cliff studies were included, and while these all showed evidence for effectiveness, the statistical power in the pooled analysis was limited.

The authors also point out that their estimates are likely to be an underestimate as they were unable to factor in cost savings associated with averted nonfatal suicide attempts.


In this economic analysis, barriers were shown to be a cost-effective suicide prevention intervention at bridge sites, but further research is required for cliff sites. However, this study provides important justification when proposing implementation of barriers at identified bridge sites, as cost is a common argument against their use. The authors note that it is difficult to factor in any substitution effect to other suicide means, and suggest qualitative studies exploring what people do if their suicide attempt by one means is thwarted (i.e. do they change their course of action for the better and seek help, or do they look for alternative means?) would be beneficial.