Infrastructure was not a widely researched topic until Aschauer identified the wider economic benefits of investment in the United States during the 1980s. Achauer's work was a catalyst for further research and debate as researchers tackled weakness in the production function approach to measurement and sought to adjust for two-way causation. The literature that followed confirmed a significant and causal connection between public investment, productivity and output and research moved to international panel data, regional economies and the relationship between infrastructure investment, output capacity, growth and productivity.</jats:p
