Simpson won with 6375 points, the bronze medal in the heptathlon at the IAAF World Championships in Helsinki in 2005 and was the first woman from Ghana, who won a medal at World Championships in Athletics.
At the 2002 Commonwealth Games she won the bronze medal with 5906 points. In the same year she won the African Championship in Radès with 6105 points. In 2003, she won at the Africa Games in Abuja with 6152 points. In 2004 she was with 6154 points champion Africa in Brazzaville. At the 2004 Olympics in Athens, she finished with 6253 points Rank 9
Simpson 's athlete ambassador of development organization Right to Play.
- Heptathlon: 6,423 points (2005 in the all-around meeting Götzis, Austria ) - continental record
- 200 m: 24.38 seconds (2007)
- 800 m: 2:17,02 minutes ( 2005)
- 100 -meter hurdles: 13.41 seconds (2005)
- High Jump: 1.85 meters (2005) - national record
- Long Jump: 6.32 meters (2005)
- Shot Put: 13.58 m (2012 )
- Javelin: 56.36 m (2005) - national record
- Grand Cross of the National Order of Ghana, one of the highest national honors