Study challenges validity of the psychological "Grit Scale"
The Grit Scale questionnaire has gained popularity over the past decade, not only in research but also in practical psychology and in employee selection. The questionnaire is used to measure grit—a personality trait combining perseverance in reaching goals and the consistency of one's interests over time. HSE researchers have found a way to prove that grit is not a single personality trait and the Grit Scale measures two independent constructs. Their findings are published in the European Journal of Psychological Assessment.
About 10 years ago, American researcher Angela Duckworth added a new term to psychology: grit, meaning hardiness of character and perseverance. Together with her colleagues, Duckworth developed the Grit Scale. It turns out that individuals who score high on the Grit Scale demonstrate greater achievement in various fields, including military training, medicine, science and competitive sports, than do others of equal intelligence and social status who have lower grit scores. Indeed, in certain cases, grit proved to be more important for academic and professional success than intelligence.
The test immediately gained popularity. Over the past 10 years, the Grit Scale has been widely used in research, and different types of achievement and success have been explained by grit. In psychology, the term has become part of the everyday vocabulary of practitioners as well as academic researchers. The questionnaire is freely accessible and quite simple, consisting of 12 statements in the long version and six in the short version—yet another factor for its popularity. In a series of publications, the authors of the concept demonstrated the reliability and internal validity of their questionnaire in measuring grit as a single personality trait. In other words, they showed that the two components of grit—perseverance of effort and consistency of interests over time—are sustainably manifested together.
However, new data emerged calling into question the existence of grit as a single trait. Based on a sample of students from the Philippines, Jesus Datu and colleagues showed that while the Grit Scale does measure both consistency of interests and perseverance, these are two distinct and independent traits that do not form a single overarching construct. According to Datu, only perseverance of effort predicted academic engagement, success and subjective well-being, while consistency of interests did not. Indeed, in his study, consistency of interests was even more common in students with low academic engagement. Datu et al. suggest that since Duckworth's study used samples from Western societies, her findings may not fully apply to the collectivist Filipino culture. Other studies conducted later on different cohorts, including Americans, also indicate that perseverance of effort and consistency of interests manifest themselves as two different constructs rather than a single one. However, explaining why the results were different from those found by Duckworth's team was still problematic.
Incidentally, physiological data proves that perseverance and consistency of interests do not necessarily correlate. When trying to solve a difficult task, mutual activation of the sympathetic and parasympathetic systems was observed in people with high perseverance scores, while high consistency of interests was associated with low activation of the sympathetic system and showed no correlation whatsoever with the parasympathetic system activation.
According to the HSE researchers, a major limitation of earlier studies was their approach to data analysis. "Their authors relied on classical test theory methods, which, despite their advantages, are unable to distinguish between the characteristics of the test and those of the subjects, while this distinction is essential," says Yulia Tumeneva, co-author of the study and senior research fellow of the International Laboratory for Education Policy Analysis. "For example, if we give a test in mathematics to a group of subjects and they get low scores, does it mean that the test was too difficult or the subjects had poor knowledge of mathematics? To answer this type of question, item response theory (IRT) can be used. IRT methods are more complex, and require special software and training in their application, but they allow us to draw a distinction between the test and subject characteristics."
The problem with grit was exactly that—whether a characteristic does not exist, or does not get captured by the questionnaire. So the HSE Institute of Education researchers applied IRT methods to a fairly large sample of high school students from a recently launched longitudinal panel study of educational and occupational trajectories using the Grit Scale.
Following a complex, multi-stage analysis, the researchers found no evidence to support the existence of grit as a single personality characteristic. Instead, the Grit Scale appears to measure two independent characteristics, perseverance of effort and consistency of interests.
These traits can, indeed, occur together—just as in some people, health can go together with kindness, or intelligence with an attractive appearance. Someone having both perseverance and consistency of interests will strive for one goal without losing interest in it over time. However, the same personality traits can also occur separately. Some people may have perseverance in reaching a certain goal, but then lose interest in it and reach out to another goal with the same perseverance, while other people may be interested in one and the same thing over years, but never set specific goals nor show perseverance in reaching them.
The so-called "Gritty person" of a specific interest of employers, for instance, is no more than a fortunate composition of two traits. So the results are rather about the accuracy of psychological terms. Practically, it means that test users have no reason to combine the scores of these two traits—perseverance of effort and consistency of interests—into an overall "grit" score, because no specific entity exists under this modern label. At the same time, it is still worthwhile to seek out tenacious and motivated workers with stable interests in your domain.