She’s only the third woman to win the prize and the first to win it alone. Professor Goldin’s work traces the historical origins of the difference between men’s and women’s wages. She trawled the archives to collect over 200 years of US data. She found that, rather than steadily increasing over time women’s employment rate fell in the early 19th century as the US economy transitioned from farming to industry. Employment rates began to close in the 20th century with the rise of the service economy. The contraceptive pill played an important role enabling women to finish education and plan careers. Now, women’s education levels in most high-income countries are higher than men's but the pay gap stubbornly persists.