But this prediction is not confirmed: the gap in earnings among people with different education, but with similar abilities, isn’t declining, but, on the contrary, increasing with the duration of their work experience. Using the filter theory it is possible to conclude, that the costs of finding capable workers among those with low qualification are so large, that they exceed the difference in pay of more or less trained working force. That’s why firms do not organize their own services for checking abilities, but use as a substitute the information about education of employees.