Ternary operator and string concatenation quirk?

Hi I just want to know why this code yields (at least for me) an incorrect result.

Well, probably i'm in fault here

$description = 'Paper: ' . ($paperType == 'bond') ? 'Bond' : 'Other';

I was guessing that if paperType equals 'Bond' then description is 'Paper: Bond' and if paperType is not equals to 'Bond' then description is 'Paper: Other'.

But when I run this code the results are description is either 'Bond' or 'Other' and left me wondering where the string 'Paper: ' went???