With her personal best of 10.82 seconds in the 100 m, Simpson is ranked 6th among Jamaican women, behind Shelly-Ann Fraser, Elaine Thompson, Merlene Ottey, Kerron Stewart and sprint veteran Veronica Campbell-Brown. Simpson's 200 mpersonal best of 22.00 seconds ranks her sixth among Jamaican women behind Merlene Ottey, Grace Jackson, Juliet Cuthbert, Veronica Campbell-Brown and Kerron Stewart. She has run this time on two occasions. Simpson is coached by Stephen Francis in Kingston, Jamaica, where she attends the University of Technology. She is also a graduate of Manchester High. Simpson won the gold medal in the women's 200 m at the 2006 Commonwealth Games, beating Olympic championVeronica Campbell and completing a Jamaican sweep of 100–200 m gold medals. Jamaica also won both sprint hurdles gold medals. At the 2008 Summer Olympics in Beijing she competed at the 100 m sprint. In her first round heat she placed third behind Yevgeniya Polyakova and Jade Bailey in a time of 11.48 to advance to the second round. There she improved her time to 11.02 seconds to win her heat in front of Muna Lee and Chandra Sturrup. With 11.11 seconds in her semi final race she placed fourth and earned her spot in the Olympic final. In a remarkable race with fellow Jamaican Shelly-Ann Fraser taking the gold, Simpson and Kerron Stewart both finished in 10.98 seconds to share the silver medal and to complete the Jamaican sweep. Together with Fraser, Stewart, Sheri-Ann Brooks, Aleen Bailey and Veronica Campbell-Brown she also took part in the 4 × 100 m relay. In their first round heat they placed first in front of Russia, Germany and China. Their time of 42.24 seconds was the first time overall out of sixteen participating nations. With this result they qualified for the final, in which they replaced Brooks and Bailey with Simpson and Stewart. Eventually they did not finish their race, due to a mistake in the baton exchange.
Doping
On 14 July 2013, Simpson informed that a urine sample she supplied after competing in the Jamaican national championships in June 2013 had tested positive for the banned stimulant oxilofrine, along with Asafa Powell. On 10 April 2014, both athletes received an 18-month suspension from competing, which was set to expire in December that year. However, after appealing to the Court of Arbitration for Sport, both athletes' suspensions were lifted on 14 July 2014.
