The model for adf is&nbsp; (1-L)y = b0 + (a-1)*y(-1) + e<br /><br />But isn't adf is using reg of change of y to lag of y? <br /><br />The (1-L)y is not refering to change of y <br /><br />Clicking the use first difference generate the same (1-L)y rather using change of y <br /><br />What does L represent?<br /><br />Clarodina<br /><br />