The employees came from a wide range of sectors including manufacturing, retail and financial services, health care, education, public sector, construction and transportation.

Loyalty was measured in three ways: by workplace seniority; whether the employee would turn down an offer of slightly more money to change jobs; and whether the employee was committed to and engaged with the company, i.e., did they buy into the company's mission even when it was outside their job responsibilities.

Linz said she was surprised to find such a strong link between worker loyalty and higher earnings.

In three countries, the contribution of loyalty to earnings was equivalent to the contribution to earnings of an additional year of experience.

Workers were more likely to be loyal if they expected to earn a bonus or learn new skills. In addition, loyalty was higher among employees who expected that doing their job well would result in job security and the feeling that they were accomplishing something worthwhile.

Praise from senior managers, however, was not always positively linked to worker loyalty.

Linz conducted the study with Linda Good, professor of advertising, public relations and retailing, and Michael Busch, a doctoral student in economics.

The findings were published in journal Evidence-based HRM.

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