To date more than 100 countries have carried out a Joint External Evaluation (JEE) as part of their Global Health Security programme. The JEE is a detailed effort to assess a country’s capacity to prevent, detect and respond to population health threats in 19 programmatic areas. To date no attempt has been made to determine the validity of these measures. We compare scores and commentary from the JEE in three countries to the strengths and weaknesses identified in the response to a subsequent large-scale outbreak in each of those countries. Relevant indicators were compared qualitatively, and scored as low, medium or in a high level of agreement between the JEE and the outbreak review in each of these three countries. Three reviewers independently reviewed each of the three countries. A high level of correspondence existed between score and text in the JEE and strengths and weaknesses identified in the review of an outbreak. In general, countries responded somewhat better than JEE scores indicated, but this appears to be due in part to JEE-related identification of weaknesses in that area. The improved response in large measure was due to more rapid requests for international assistance in these areas. It thus appears that even before systematic improvements are made in public health infrastructure that the JEE process may assist in improving outcomes in response to major outbreaks. This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.