How to get the increase/decrease change of a variable?

[meety99]

Hi ,

My model is as below:

"Inflation Rate=" c "+ Output gap" +"Import price",

I am going to test whether the increase in output gap and the decrease in output gap have the symmetric effect on Inflation rate, so my model becomes two equation, I am going to put these two equation in an System:

delta (inflation rate)_"positive" =c +delta (output gap)_"positive"
delta (inflation rate)_"negative" =c +delta (output gap)_"negative"

But I don't know how to get the variable delta (inflation rate)_"positive"
from the the data of inflation rate? Could anyone give me some advice, thanks.

[startz]

What precisely do you mean by delta (inflation rate)_"positive"?

[trubador]

I think your model is ill-defined, and the correct approach would be something to what Startz has suggested in your previous post. Regarding to your question, you can generate the series with the following expressions:

Code: Select all

series inf_positive = (d(inflation_rate)>0)*d(inflation_rate)

or

Code: Select all

series inf_positive = @recode(d(inflation_rate)>0,d(inflation_rate),0)

[meety99]

What precisely do you mean by delta (inflation rate)_"positive"?

Thanks for your reply, sorry for the confusion, I am just wondering how get a series of "change value of the data", is it just d(inflation rate)?

[meety99]

I think your model is ill-defined, and the correct approach would be something to what Startz has suggested in your previous post. Regarding to your question, you can generate the series with the following expressions:

Code: Select all

series inf_positive = (d(inflation_rate)>0)*d(inflation_rate)

or

Code: Select all

series inf_positive = @recode(d(inflation_rate)>0,d(inflation_rate),0)

Thanks a lot for your reply, it is helpful, I think I do have some problem with my model, I'd better define a reasonably model first:-)

[startz]

What precisely do you mean by delta (inflation rate)_"positive"?

Thanks for your reply, sorry for the confusion, I am just wondering how get a series of "change value of the data", is it just d(inflation rate)?

That's right.