now make variables for inverse items It easy to do it [Maximum value among response +1] - [actual response values] for example, someone response item 1 as 2, in Likert scale(5) change the value 2 to 4(6-2=4) But.. How do I know which item is inversed? there are three way to check first, Check the GuideBook about the item. item developer would write about it second, Check correlation among items ..