Why has the gender wage gap narrowed?

This is from a report by Marie Drolet, who is with the Social Analysis Division of Stats. Canada.

The female to male earnings ratio, based on full year, full time workers, has held steady at .72 since the early 1990's. This contrasts with the preceding 20 years, during which there was a steady, but modest narrowing of the earnings gap.

Some of the points from this study:

• Job tenure - women more likely to now be working for longer periods
• Proportion of women in unionized jobs has been higher than the corresponding figure for men
• Women's wages grew faster than men's
  
• Wage gap narrowed most among older workers
• Changes in educational attainment for women
• For older workers, longer job tenure and shits in occupation reduced the gap
• Higher education and declining unionization narrowed the gap for younger workers
• Interesting, the average hourly wages of young men in manufacturing fell by about 2% between 1988 and 2008, but rose by roughly 10% for younger women.
• Declining correlation between wage gap and age

Major finding - that the growth in women's relative wages outspaced that of men - suggests that the changing composition of the labour force and changes in how the labour market compensates workers played a role in narrowing the gender wage gap. Second major finding, that men and women entering today's labour market are more alike in terms of characteristics and wages than they were in the past.

Thirdly, that cross-sectional evidence tends to overstate the correlation between the wage gap and age - suggests that part of the decrease in the gender wage gap is related to the fact men and women's wages did not diverge as they aged to the same extent as in the past.