Oxford "British and World English" dictionary, post-mortem: "An analysis or discussion of an event held soon after it has occurred, especially in order to deter

Oxford "British and World English" dictionary, post-mortem: "An analysis or discussion of an event held soon after it has occurred, especially in order to determine why it was a failure." https://en.oxforddictionaries.com/definition/post-mortem https://en.oxforddictionaries.com/definition/post-mortem. Maybe not common in the UK, but I'd say it's perfectly correct word usage.