This involves combining the insights from both experts and non-experts, to reap the benefits of diversity of thought and action. But this larger pool is not so large as to dilute the time available for slow-thinking and deliberation. It is a cocktail of expert and non-expert opinion, comprising diversity and deliberation in equal measure, that cause good ideas to flourish and bad ones to perish. A relevant, practical question is where the optimal point along the insight curve lies. What is the optimal number of people from whom to seek views if we are to maximise the benefits of folk wisdom? My stylised example cannot provide an answer to that question. But some studies have looked at this question using experimental methods and, reach interesting conclusions. Christian Wagner and Tom Vinaimont ask two questions. 39  First, how large does a group of non-experts  need to be to exhibit expert-like performance? Second, how large does this group need to be to outperform consistently a group of experts? On the assumption experts’ views are ten times more precise than a non-expert, their answer to the first question is around 30 and the second around 1,000. This bookends the range of non-expert views we might need in seeking the “wisdom of crowds”. Representative Decision-Making  If we take this analysis at face value, the question is how practically central banks can engage a wider, non-expert, audience to help inform their views on the economy and financial system?

King, M (2003), speech available at https://www.bankofengland.co.uk/-/media/boe/files/speech/2003/east-midlands-development-agency-dinner Kydland, F and Prescott, E (1977), ‘Rules Rather than Discretion: The Inconsistency of Optimal Plans’, Journal of Political Economy, Vol. 85, No. 3, pp. 473-492. Kynaston, D (2017), Till Time’s Last Sand: A History of the Bank of England 1694-2013, Bloomsbury Publishing. Mackay, C (1841), Extraordinary Popular Delusions and the Madness of Crowds, Richard Bentley. Mankodi, A and Pike, T (2018), ‘Can central bankers become Superforecasters?’, Bank Underground, 12 March 2018. Nelson, E (2005), ‘The Great Inflation of the 1970s: What Really Happened?’, Advances in Macroeconomics, Vol. 3. Newman, N, Fletcher, R, Levy, D and Nielsen, R (2016), ‘Reuters Institute Digital News Report 2016’, Reuters Institute for the Study of Journalism. Page, S (2008), The Difference: How the Power of Diversity Creates Better Groups, Firms, Schools, and Societies, Princeton University Press. Papacharissi, Z (2002), ‘The virtual sphere: the internet as a public sphere’, New Media & Society, Vol. 4, No. 1, pp. 927. Richardson, T, Elliott, P, Roberts, R and Jansen, M (2017), ‘A Longitudinal Study of Financial Difficulties and Mental Health in a National Sample of British Undergraduate Students’, Community Mental Health Journal, Vol. 53(3), pp. 344352. 26  All speeches are available online at www.bankofengland.co.uk/speeches  26  Roubini, N and Mihm, S (2011), Crisis Economics: A Crash Course in the Future of Finance, Penguin. Shafik, M (2017), ‘In experts we trust?’, speech available at https://www.bankofengland.co.uk/speech/2017/in-experts-we-trust Shiller, R (2017), ‘Narrative Economics’, American Economic Review, Vol 107, No. 4, pp. 967-1004.