Advance sorry for asking such a naive doubt in Stata. I have 2 variables, 1.cash holdings and 2.total assets. I need to find say, change in cash holdings. However, for interpretation purpose, I am scaling variable cash holdings by total assets (to imply % of cash in total assets). Now, my question is for change in cash holdings, should I calculate [cash holdings(n)-cash holdings(n-1)]/total assets or [cash holdings(n)/total assets(n)]-[cash holdings(n-1)/total assets(n-1)]?In the second case I think that we are calculating the difference between two proportions, whereas in the first case , the difference between the two absolute value is scaled. Which one is econometrically correct?