In 2017, Zitelmann’s study on ultrarich individuals with assets in the tens and hundreds of millions was published as "The Wealth Elite: A Groundbreaking Study of the Psychology of the Super-Rich", which was based in part on in-depth interviews with 45 exceptionally-wealthy individuals. The study took the form of a qualitative social science study, as there are too few representative cohorts for a quantitative study of the super-rich. Most of the study's interviewees were self-made multimillionaires. The study shows that a high proportion of the super-rich were engaged in entrepreneurial activities as early as their school and/or university days. One of the study’s most striking findings is that many of the super-rich were highly competitive athletes in their youth. In contrast, their educational achievements did not play a decisive role in the level of wealth thaf they attained: the upper quartile of interviewees (assets of US$330 million to US$3.3 billion) had more members without a university degree than did the lower quartile (assets between US$11 and US$33 million). In their decision-making, Zitelmann's wealthy interviewees tended to act intuitively, rather than be guided by analysis. The study found that implicit knowledge gained as a result of implicit, often informal, learning experiences played a far more significant role than academic education. All of the interviewees completed a Big Five personality test. It revealed that conscientiousness was a particularly-strong trait and neuroticism a particularly-weak trait. Extraversion and openness to new experiences were also pronounced traits. That corresponds with the findings of previous research.