Group Comparison Tools - Adjusting Changes vs. Levels

[mrgordon]

Hello,

I am using the Group Comparison Tools when overriding series in my models. I am confused by how EViews seems to adjust the levels under certain circumstances, and the changes under other circumstances.

I am using EViews 8 Enterprise 64-bit on Windows 7.

Example:
I am starting with series A and B both = 1.

Starting point

group1.PNG (26.59 KiB) Viewed 1981 times

If I make changes to @PCHA(A), the series A level increases in that period and continues at that level going forward.

@PCHA change

pcha.PNG (31.74 KiB) Viewed 1981 times

If I revert the change, switch to making changes to @PCHY(A), and make a change, the series A level only increases in that specific period.

@PCHY change

pchy.PNG (27.34 KiB) Viewed 1981 times

It seems that for @PCHA(A), EViews keeps the change to the level applied through the rest of time, whereas changing @PCHY(A) only alters one time period's level.

Can you please explain why the changes seem to have different impacts? Is there a way to choose the impact? For instance, if I want to change the @PCHY(A) to 1%, but keep the adjusted level of A for the rest of time.

Thank you,

Mike