I’m reading a whole bunch of posts saying, “I have tattoos and am normal.” The study examines a statistically significant sample and finds that those with tattoos are more likely to experience a group of outcomes and behaviors, all bad.
The study doesn’t say everyone with a tattoo is a loser, just that they are more likely to be losers. I don’t think we needed a study to determine that, but having the numbers is interesting nonetheless.
People form opinions and draw conclusions about us based, in part, on the choices we make regarding our appearance. Sometimes the conclusions are in error. For example, one may see an immodestly-dressed girl and conclude that she is promiscuous, when she is not. An employer may believe that an applicant without tattoos is more likely to show up on time, sober, and not steal. Due to the coincidence of tattoos with drug use and prison, this is not an unreasonable belief, although it may be inaccurate in the individual case.
As many comments have observed, tattoos are more common and more admired by younger people. That fact could explain some of the correlation of tattoos with lower incomes, because younger people, on average, have lower incomes than older ones.