This paper conducts a meta-review of 18 empirical studies to discover which cybersecurity controls most reliably reduce rea-world cyber risk for organizations. It aims to give policymakers evidence-based guidance on which controls matter the most and how policy can support their deployment. The studies had to analyze real organizations facing real attackers, measure concrete security control, and link those controls to outcomes that matter to the organization. The largest risk reduction intervention in every study that measure it was attack-surface management/hardening. Multi-factor authentication and fast patching of high-severity vulnerabilities were also extremely strong predictors of lower incident/claim rates. The main policy implications found were to avoid prescriptive “checkbox” mandates, funding and maintaining resources like CISA’s Known Exploited Vulnerabilities, encourage “secure by design” infrastructure choices, and expand public data on incidents. The paper emphasizes that policymakers should invest less energy in mandating specific security products and more in enabling organizations to implement high-leverage practices well.
