When hiring new staff, conscientiousness and emotional stability are two criteria often near the top of any recruiter’s list. They are commonly seen as key personality characteristics influencing job performance.

After all, a conscientious employee is dependable, persistent, organized and goal directed. One who is emotionally stable is calm, steady under pressure and less likely to experience negative emotions such as anxiety, depression and anger that might distract attention from the job at hand.

So, the more conscientious and emotionally stable the better. Right?

Research commentary
This article is based on the research paper Too Much of a Good Thing: Curvilinear Relationships Between Personality Traits and Job Performance co-authored by Huy Le, TUI University; In-Sue Oh, Virginia Commonwealth University; Steven B. Robbins, ACT Inc.; Remus Ilies, NUS Business School / Michigan State University; Ed Holland, Iowa Department of Administrative Services; Paul Westrick, University of Iowa.

It was published in the Journal of Applied Psychology. The full paper can be downloaded here

Not quite. In fact you can have too much of a good thing.

Rather than being a flat, linear relationship, the effect of these personality traits on job performance is curved – there comes a point where employees can be too conscientious and too emotionally stable.  So much so, in fact, that it begins to undermine job performance.

With conscientiousness, for example, taken to an extreme what starts out as a virtue becomes an impediment. Excessively conscientious people can become rigid, inflexible and compulsive perfectionists. Too much attention is given to small details while the more important goals needed to accomplish the key tasks are overlooked.


Highly conscientious people are also more prone to self-deception, thinking they already know what they need to know. Since the way they do their job is the best, there is no reason to change. In an era where innovation and constant improvement is key, such rigidity inhibits them from learning and ultimately leads to sub-par performance.

By better understanding the relationship between personality characteristics and job performance we can improve the process of personnel recruitment and deliver more accurate predictions

Similarly, while being emotionally stable helps people to concentrate on what is relevant to the task at hand, taken to an extreme makes one obsessively focused on accuracy at the expense of attending to other aspects necessary to do the job right. Indeed, it could well be argued that a moderate degree of anxiousness makes an employee better able to anticipate potential problems or roadblocks and therefore a better performer.

Our research in this area has shown that employees who are highly conscientious or emotionally stable not only see reduced job performance but can display poorer corporate citizenship. In other words they are less helpful or supportive to their co-workers.

By being a stickler to the rules and the formal responsibilities of the job they become inflexible. As a result they become less likely to be involved in behaviors beyond their job description, even when that may be of value to the company.

Does this mean that companies should avoid employing people who are highly conscientious and emotionally stable?

Changing demands

ThinkAloud4Not necessarily. Our research has found that in more complex jobs with high intellectual and frequently changing demands, extreme personality characteristics can deliver exceptional performance.

When jobs are not so complex (for example, a fast-food restaurant employee), they usually demand both speed and accuracy. Here the deliberate, cautious and dutiful nature of an extremely conscientious employee will lead them to waste time, resulting in slower work at the expense of accuracy, and hence, poor performance. For such jobs, being moderately conscientious is sufficient and desirable.

However jobs of high complexity usually require accuracy over speed (for example, accountant, financial analyst) and creativity (scientist, engineer), both of which are attained through persistence and dutifulness – the hallmarks of being highly conscientious.

For very emotionally stable employees put on complex jobs we noticed that they continue to perform better in terms of being a better corporate citizen, but not the job itself.

By better understanding the relationship between personality characteristics and job performance we can improve the process of personnel recruitment and deliver more accurate predictions. Instead of assuming that the more conscientious or emotionally stable an applicant is, the better performer that person will be, companies may do well to have a selection practice based on cutoff points.

For low complexity jobs, companies may want to exclude job applicants with very high scores on conscientiousness and emotional stability. The cutoff point should be adjusted depending on the level of job complexity. Arguably, such a selection system can help improve the usefulness of personality tests in personnel selection.

From a potential employees’ perspective, these findings suggest that for candidates who consider themselves conscientious and emotionally stable, learning to be adaptable can help them deliver optimal performance across different tasks.

After all, not all tasks that come under one job are similarly complex. To do well, some tasks do not require as conscientiousness or calmness as others.

In such instances, employees can conserve their energy and avoid burning out by being constantly on top of their game, thus reducing employee wearout and turnover.