Psychologists have spent over 100 years investigating the determinants of career success. Their conclusion has remained unchanged for 30 years: IQ is the most important predictor of job performance, followed by integrity (and the former can be measured much more precisely than the latter). Is that all there is? Not really: We now have hundreds of meta-analyses showing that a wide range of pyschological and physical variables—from charisma to height and attractiveness—also determine the degree to which you are likely to succeed in business. Unfortunately, there have been few attempts to integrate all these variables and there is also a great deal of confusion regarding similar constructs that receive different labels (e.g., social skills and emotional intelligence) and different measurement approaches for the same constructs (e.g., performance tests, situational judgment tests, self-reports, 360-degree feedback, etc.). This has led academics to re-affirm that there is nothing as powerful as IQ, and that abstract cognitive ability is the most important determinant of individual differences in career success.
On the other hand, recruiters and managers seemed to have come off IQ tests a while ago and at most regard cognitive ability as one of many competencies they look for in employees and job applicants. Indeed, real-world data suggests that big organizations (who are the main users of psychological assessment tools) are using fewer and fewer IQ tests for selection, and their use in training has never been promoted as IQ scores remain practically unchanged through adult life. So, are employers ignoring important evidence from the "scientists" of career success, or is the science of the psychological determinants of job performance somewhat detached from real-world business practices? Should best-practice be more aligned with the empirical evidence or should academics pay more attention to managerial know-how?
There are probably two big reasons for the discrepancy between academic recommendations and professional practices in human capital. The first is that most of the studies highlighting the importance of IQ as predictor of career success use objective performance measures as criterion—and when was the last time your performance was assessed objectively? In most jobs and for most people, performance is what their managers think about their work (and that opinion is also dependent on how much they like their employees). The second reason is that academic studies of career success tend to exclude a substantial proportion of real-world employees. Think about it: the global market for psychometric testing in employment is probably lower than 20-million people a year, and 40% of the workforce are self-employed at some point in their lives (at least in places like the UK and the US). The simple truth is that most people never complete psychometric tests as part of their staffing or training process, and a tiny fraction of those people have their performance assessed objectively. These two reasons may be irrelevant to explain the main findings of academic psychologists, but they are good candidates to explain why laypeople and managers alike are so disinterested in IQ tests.
Why, then, are some people more successful in their careers than others? Is it all just luck, or the people you know? Is it socio-economic status, or being in the right place at the right time? Can psychology still help us understand why some people do better at work than others? I think so. But key to understanding these issues is to accept the realities underlying managerial practices in the real-world. In addition, it would be useful to have a really simple, but integrative, model of career success psychology. This model would need to account for what employers really want in employees, rather than what they say they need. For instance, employers say they look for creative employees, but creative employees are hard to manage because they are unpredictable. Predictable people are much easier to manage and constitute less of a risk to bosses. Managers are also less interested in top performance than they are in employees who can minimise their workload: indeed, getting stuff done quickly, being efficient, delivering exactly what your boss wants, will be rewarded more than creative or exceptional performance (which may differ from your managers' expectations). And the final point is rather obvious - but academics rarely discuss it - people who suck up to their bosses will inevitably outperform those who don't. And we don't need any academic studies to confirm this!
In short, the secret to a successful career is this: be predictable, minimize your bosses' workload, and suck up to them—and this is also why personality determines your career success. People who are likeable, reliable and hard-working will do better in any job, and being likable, reliable and hard-working depends on your personality.