Interpretation of second difference of a predictor

#1
Hi,

can you please help with this -
If I have a regression equation to predict Y using one of the independent variables which uses the second difference transformation, how can I interpret this in business sense. For instance if I am forecasting GDP of a country using S&P 2nd difference, what is the interpretation in theoretical sense
 
#4
Yous said earlier: " using S&P 2nd difference". How is that "the change in absolute changes"? You would need to state clearly what's going on.
 
#6
To some extent, the second difference is measuring whether the companies have generated more casfflows than last year or less.