Occupational segregation refers to the way that some jobs (such as truck driver) are dominated by men, and other jobs (such as child care worker) are dominated by women. Considerable research suggests that predominantly female occupations pay less, even controlling for individual and workplace characteristics. Economists Blau and Kahn stated that women's pay compared to men's had improved because of a decrease in occupational segregation. They also argued that the gender wage difference will decline modestly and that the extent of discrimination against women in the labor market seems to be decreasing.