The definition of the time period is discussed further in Annex 4.B.) In sum, the nature of the data available prevents more detailed examination of which type(s) of state dependence are the most important in the context of SA receipt dynamics. Bhuller, Brinch and Kdnigs find however that estimates of the level of state dependence can vary significantly with the level of time aggregation. Some researchers fitting DREP models to annual unemployment histories have taken a practical approach to try and identify Markovian state dependence separately from duration dependence.