Two different constructs
IQ measures cognitive abilities: reasoning, memory, processing speed. EQ — emotional quotient — refers to a cluster of skills around recognising, understanding, and managing emotions, both your own and other people's.
Both can be measured, but with very different reliability. IQ tests have nearly a century of psychometric refinement behind them. EQ tests vary widely: some are self-reports that mostly measure how you wish you were, while others use performance items that ask you to identify emotions in faces or pick the most adaptive response to a scenario.
Do they predict different things?
Decades of research show that IQ is the single best predictor of academic performance and a strong predictor of job performance in complex roles. It correlates with income, education, and health outcomes — though always as one factor among many.
EQ predicts a partly different set of outcomes: quality of relationships, leadership effectiveness, conflict management, and resilience under stress. In jobs where emotional labour matters — sales, teaching, healthcare, management — EQ adds predictive value beyond what IQ alone explains.
Are they correlated?
Mildly. People with higher cognitive ability tend to score somewhat higher on performance-based EQ tests, probably because identifying emotions accurately is itself a reasoning task. But the overlap is small enough that the two should be treated as distinct.
Which one matters more?
The honest answer is: it depends on the goal. For passing a calculus exam, IQ matters more. For navigating a tense team meeting, EQ matters more. Most real lives require both, in different proportions at different moments.