The study looked at how international inspections by the PCAOB affect audit quality for foreign public companies. The researchers found that these inspections improved audit quality for both Big 4 and non-Big 4 auditors in foreign countries, with a greater impact on non-Big 4 auditors. This means that the inspections helped raise the quality of audits for companies listed outside the US, even for auditors not directly overseen by the PCAOB. This suggests that the inspections have a positive spillover effect on audit quality in foreign markets, benefiting both PCAOB-registered and non-PCAOB-registered auditors.