It's a meta-study aggregating about 13 surveys. The things being measured by the underlying surveys vary but mostly seem to center on government-employee bribe

It's a meta-study aggregating about 13 surveys. The things being measured by the underlying surveys vary but mostly seem to center on government-employee bribery and misuse of public funds. Most of the surveys are expert surveys not of the general public, and some of them use out-of-country researchers. It looks like 3 of the surveys reported data for NK and they're all outsiders.