The group of Christians known as the Christian Churches or Churches of Christ are congregations within the Restoration Movement (also known as the Stone-Campbell Movement and the Reformation of the 19th Century) that have no formal denominational affiliation with other congregations, but still share many characteristics of belief and worship. Churches in this tradition are strongly congregationalist and have no formal denominational ties, and thus there is no proper name that is agreed to apply to the movement as a whole. Most (but not all) congregations in this tradition include the words "Christian Church" or "Church of Christ" in their congregational name. Due to the lack of formal organization between congregations, there is a lack of official statistical data, but the 2016 "Directory of the Ministry" documents some 5000 congregations in the USA and Canada; some estimate the number to be over 6,000 since this directory is unofficial.