Complex sentence: In 1926, George Taylor the Hemline index theory, which holds that hemlines on women's dresses fluctuate with the economy, measured by stock prices or gross domestic product, which still receives regular attention in the media and, in 2010, some academic validation.
Split into simpler sentences: In 1926, George Taylor introduced the Hemline index theory, which holds that hemlines on women's dresses fluctuate with the economy, measured by stock prices or gross domestic product. The "theory" still receives regular attention in the media and, in 2010, some academic validation.