"For US states, the indicators described above are aggregated into four policy indices, each of which measures a different set of government responses (the indicators that make up each index are listed in Table 2):

1. A containment and health index, showing how many and how forceful the measures to contain the virus and protect citizen health are (this combines 'lockdown' restrictions and closures with health measures such as testing policy and contact tracing) ^*
2. An economic support index, showing how much economic support has been made available (such as income support and debt relief)
3. A stringency index, which records the strictness of 'lockdown style' closure and containment policies that primarily restrict people’s behavior
4. An overall government response index which records how the response of states has varied over all indicators, capturing the full range of government responses

^* Because the term "lockdown" is used in many different ways, we do not define this term here but instead refer to the number and restrictiveness of closure and containment policies."