Having read the paper, it is based on expert classifications and summaries of job titles...it is like a game of telephone, where real world -> noisy data colle

Having read the paper, it is based on expert classifications and summaries of job titles...it is like a game of telephone, where real world -> noisy data collection -> noisy data classification -> noisy expert analysis -> specific study -> paper leads to something where the paper is just too disconnected from the real world.