16 May, 2022

Two step lottery sortition selection in the USA

The way we (and most other deliberative democracy organisations) perform a democratic lottery for events such as citizens' assemblies is in two steps:

  1. Randomly select a number of people or addresses or phone numbers from the most up-to-date available database and invite those randomly selected people to register their interest in the assembly.
  2. From those that express an interest, perform a second lottery in the fairest way possible, matching socio-economic and demographic (and sometimes attitudinal) targets, to correct any skewing in the pool of interested people so the final assembly is a microcosm of the community.

You can see several detailed examples of this process on our other posts, for example in Birmingham (on making homes net zero), in Jersey (on assisted dying) or in Victoria, Australia. These examples are from the UK or Australia, where the first step is performed using Royal Mail's postal address database or Australia Post's address database, respectively. In these cases, any person who lives in the household selected can register, but a maximum of one person from any given household will be selected. When we have partnered with the Budapest City Council in Hungary they contact the relevant national ministry who randomly selected people from the national resident register for the first step.

In the US it is our understanding that most organisations use the voter registry database, but obviously these databases are incomplete and non-citizens can never be selected to participate (note that in both the UK and Australia almost all the citizens' assemblies we have conducted have allowed non-citizens to participate). Of course, we assume that the USPS must have a database of all addresses (as they offer address checking services...) but their website states "The Postal Service does not keep a database of residential or business customers and does not sell address lists" so we assume that even if they do they are not selling (or giving away for a good cause?) that data...

However, the US Department of Transportation has started creating such a database (the NAD), navigating each state's systems and slowly putting this together where possible. It looks to us like it currently (as at May 2022) covers approximately 30 of the 50 states, and more should be added over time.

So we have jumped in and written some lottery address selection software based on zip codes, to perform Step 1 of the process above in the US. We tested it by randomly selecting 2000 households from the zip codes for Phoenix, Arizona (as listed on this website). The two images below are from the map of these addresses - one zoomed out and one zoomed in.

What does this mean? This means that, given a set of the relevant zip codes, the Sortition Foundation can now do an entire 2-step, postal-registration and stratified random selection process in any area of those US states covered by the US National Address Database. Do contact us if that is of interest to you, or if you have any questions or comments on any of the above - we'd love to hear from you!



We use cookies on our websites. You are free to manage this via your browser setting at any time.