A ranking of possible policies or strategies according to their effectiveness in various future scenarios. The options are categorised as “no regrets,” which are effective in all scenarios; “opt-out” options, which are effective in most scenarios but may need to be opted-out of in some situations; “opt-in” options, which are effective in a minority of scenarios, requiring investment in capabilities in case they need to be opted-in at a later date; and “abandon” options, which are ineffective in all scenarios.