 Simpson has had shadow ministerial responsibility for Health, Transport, Main Roads, Tourism, Women, Communities, Housing and Waste Watch, in addition to having been elected Deputy Leader of the Queensland National Party (and therefore Deputy Leader of the Opposition) on 18 September 2006.While Deputy Leader, Simpson was a key player in the merger with the Queensland Liberal Party, which created the Liberal National Party of Queensland.She voluntarily stepped aside as Deputy Opposition Leader in favour of Liberal Party Leader Mark McArdle to help facilitate the merger.