How do I calculate the value distance between positive and negative scales?

[Madison Stock]

Hello,

I am trying to produce an attitudinal ambivalence measure that captures both similarity and extremity of co-existing positive and negative sentiments. I have scales that indicate positive sentiments toward their parent and scales that indicate negative sentiments.

Simply, I need to calculate the following formula:

[(positive + negative)/2 - |positive - negative|]+1.5

I am unable to figure out how to calculate "| positive - negative |", which is the distance between the positive and negative values on each scale. Is this possible in STATA? I can not find an answer anywhere.

Thank you.

[Ken Chui]

I am unable to figure out how to calculate "| positive - negative |"

That's the absolute value, can be computed with:

abs(positive - negative)