According to Willigan and Lynch, the main sources used by demographic historians include archaeological methods, parish registers starting about 1500 in Europe, civil registration records, enumerations, national census beginning about 1800, genealogies and family reconstruction studies, population registers,[6] and organizational and institutional records. Statistical methods have included model life tables, time series analysis, event history analysis, causal model building and hypothesis testing, As well as theories of the demographic transition and the epidemiological transition.[7][8]