Dear Yuantzu Chieh, but isn't the direction of change directly visible from the values of your variables in all groups at T1 and T2? The difference between T1 and T2 should indicate whether the variable is increasing or decreasing in a given group.

After performing the Scheirer-Ray-Hare test, you can use post-hoc tests to determine which groups differ significantly from each other. Once you have identified which groups are significantly different, you can then examine the mean values for the variables of interest at each time point to determine the direction of change.

One approach is to calculate the mean difference between T2 and T1 for each group, and then compare the mean differences across groups. If the mean difference is positive, it indicates an increase in the variable from T1 to T2, while a negative mean difference indicates a decrease. You can use a paired t-test or Wilcoxon signed-rank test to determine whether the mean difference is significant within each group.

Another approach is to calculate the percentage change between T2 and T1 for each group, and then compare the percentage changes across groups. This approach can be useful when the variable values at T1 are not comparable across groups. For example, if one group has much higher values at T1 than the other groups, a percentage change may be more informative than a mean difference.

In addition to examining the mean differences or percentage changes, you can also create plots or graphs to visualize the changes in the variables over time within each group. This can provide a more intuitive understanding of the direction and magnitude of the changes.

It is important to note that the direction of change may not always be clear or straightforward, especially if there are complex interactions between the groups and time points. In some cases, it may be necessary to conduct additional analyses, such as regression or mixed-effects models, to fully understand the patterns of change in the variables of interest.