The nationwide survey has a ± 1.4% error margin at the 95% confidence level. Subnational estimates for the geographic areas covered in the survey have the following error margins at 95% confidence level: ± 4% for Metro Manila, ± 2.1% for the rest of Luzon and ± 3% for Visayas and 2.8 for ± Mindanao. – Rappler.com