In the 1960s the Roskill commission was tasked with producing a report into the best location for the third London airport. Its findings were reached though cost-benefit analysis, assigning an arbitary economic value to the unquantifiable. The report famously valued a Norman church at just £50,000 (the cost of its fire insurance).
As contermporary detractors noted, reports based on cost-benefit analysis carry the predjudices of their authors - and Roskill was no exception. The greatest weight was given to convenience of passengers, calculated by applying a per-minute value for any reduction in journey times to the combined number of minutes saved by the total number of passengers who might use the airport over a ten or twenty year period! Saving just one second per passenger would add up when aggregated over a decade or two - even if that second was saved by drastically increasing noise and pollution.
