Invalid argument schema

Invalid argument schema: An argument form or skeleton such that if its variables are appropriately replaced making all its premises true, then it is still possible that its conclusion may be false (assuming no methodological flaws in the argument).

Source: What is Good? What is Bad? The Value of All Values across Time, Place and Theories’ by John McMurtry, Philosophy and World Problems, Volume I-III, UNESCO in partnership with Encyclopedia of Life Support Systems: Oxford, 2004-11.