How did we work this out?
To produce the figures you see in Shape Our City economists had to first forecast what health impacts might occur in an average year amongst a standard group of 1,000 people. This forecast is based on what has been observed from medical studies on urban health.
Using evidence from valuation studies, the net cost or savings to society from these impacts was then calculated. These figures include the cost or savings to not just medical care; social care and lost earnings – for employer and employee – were also factored in. They also included values to represent people’s ‘willingness to pay’ to avoid the risk of premature death and the pain and suffering associated with a disease. By including all these factors, the figures provide a more complete picture of the impact city design has on us.
Neighbourhoods contain roughly 10,000 people so the economists multiplied the ‘standard group’ by 10. To get to city level, the standard group was multiplied by 500, in order to represent a city like Bristol, which has a population of just under 500,000. They then calculated total costs for 25 years to produce a metric which is comparable with infrastructure timescales.
Implementation costs were worked out by collecting evidence from reported cases of successful real-world interventions at the neighbourhood and city wide scale, also using the same 25 year timescale.
These research findings have emerged from a national transdisciplinary research project called UPSTREAM. This project has gathered the latest evidence on a range of health outcomes that result from the design of cities, from mental health to cancer and coronary heart disease. This is based on the understanding that health and wellbeing is affected by a range of factors, particularly those relating to the environment in which people live. You can find out more about this project here.