Table 6 Mean of differences in slope change estimates between methods (row method—column method) (top triangle) and geometric mean ratio of standard errors for slope change between methods (column method/row method) (shaded bottom triangle) with 95% limits of agreement. The NW and OLS methods use the same estimator for level and slope change, as do REML and REML-Satt (not shown), which also use the same estimator for standard errors