The race to the White House is a close call with the two candidates neck-and-neck in the days before the election. Use our polltracker to follow the changing support for Democratic incumbent Barack Obama and his Republican rival Mitt Romney.

The BBC poll of polls uses the same methodology as the London School of Economics, known as the median smoothing method.

Looking at the five most recent polls it takes the middle value for each candidate, ie, the value which falls between two figures that are higher and two figures that are lower.

Polls compiled in the poll tracker Poll Obama Romney Date Margin of Error Sampling Method Pew Research 50 47 4 Nov +/-2.2 2709 LV Gallup 49 50 4 Nov +/-2 2700 LV ABC News/Wash Pos 50 47 4 Nov +/-2.5 2345 LV CNN/Opinion Research 49 49 4 Nov +/-3.5 963 LV Pew Research 50 47 3 Nov +/-2.2 2709 LV ABC News/Wash Post 49 48 3 Nov +/-2.5 2069 LV ABC News/Wash Post 49 49 30 Oct +/-3.0 1288 LV ABC News/Wash Post 49 48 29 Oct +/-3.5 1271 LV ABC News/Wash Post 49 49 28 Oct +/-3.5 1259 LV Gallup 46 51 28 Oct +/-2 2700 LV Pew Research 47 47 28 Oct +/-2.9 1495 LV Gallup 46 50 27 Oct +/-2 2700 LV ABC News/Wash Post 48 49 27 Oct +/-3 1382 LV Gallup 46 50 27 Oct +/-2 2700 LV Reuters/Ipsos 47 46 26 Oct +/- 2.6 1141 LV ABC News/Wash Post 47 50 26 Oct +/-3 1382 LV ABC News/Wash Post 48 49 25 Oct +/-3 1382 LV Gallup 46 51 25 Oct +/-2 2700 LV ABC News/Wash Post 48 49 23 Oct +/-3 1382 LV Gallup 47 50 23 Oct +/-2 2700 LV Reuters/Ipsos 47 44 17 Oct +/- 3.3 1141 LV Gallup 46 50 16 Oct +/- 3 2723 LV Reuters/Ipsos 46 43 16 Oct +/- 2.6 1846 LV Reuters/Ipsos 47 45 15 Oct +/- 2.6 1864 LV Reuters/Ipsos 46 45 14 Oct +/- 2.5 1793 LV ABC News/ Wash Post 49 46 13 Oct +/- 3.5 923LV Gallup 49 46 8 Oct +/-2 3050 RV Pew Research 45 49 7 Oct +/-3.4 1112 LV CNN/Opinion Research 50 47 30 Sept +/-3.5 783 LV ABC News/Wash Post 49 47 29 Sept +/-4 813 LV Gallup 50 44 28 Sept +/-2 3050 RV Gallup 47 47 19 Sept +/-2 3050 RV Pew Research 51 43 16 Sept +/-2.4 2268 LV CBS News/NY Times 49 46 12 Sept +/-4 1162 LV Reuters/Ipsos 48 45 10 Sept +/-3.4 873 LV ABC News/Wash Post 49 48 9 Sept +/-4.5 710 LV CNN/Opinion Research 52 46 9 Sept +/-3.5 709 LV Gallup 49 44 9 Sep +/-2 3050 RV CNN/Opinion Research 48 48 3 Sep +/-3.5 735 LV Gallup 47 46 1 Sept +/-2 3050 RV ABC News/Wash Post 46 47 25 Aug +/-4 857 RV CNN/Opinion Research 49 47 23 Aug +/-3.5 719 LV Gallup 45 47 21 Aug +/-2 3050 RV Gallup 46 46 11 Aug +/-2 3050 RV Gallup 47 45 1 Aug +/-2 3050 RV Pew Research 51 41 26 July +/-3.2 1956 RV Gallup 46 46 25 July +/-2 3050 RV CBS News/NY Times 46 47 16 July +/-3 942 RV Gallup 47 44 11 July +/-2 3050 RV Reuters/Ipsos 49 43 9 July +/-3.4 885 RV Pew Research 50 43 9 July +/-2.3 2373 RV ABC News/Wash Post 47 47 8 July +/-4 1003 RV CNN/Opinion Research 49 46 1 July +/-2.5 1390 RV Gallup 48 43 28 Jun +/-2 3050 RV Pew Research 50 46 17 Jun +/-2.9 1563 RV Gallup 45 46 14 Jun +/-2 3050 RV Reuters/Ipsos 45 44 11 Jun +/-3.4 848 RV Gallup 46 45 8 Jun +/-2 3050 RV Pew Research 49 42 3 Jun +/-2.3 2388 RV CNN/Opinion Research 49 46 31 May +/-3.5 895 RV Gallup 47 44 30 May +/-2 3050 RV ABC News/Wash Post 49 46 20 May +/-4 874 RV Gallup 45 46 17 May +/-2 3050 RV CBS News/NY Times 43 46 13 May +/-4 562 RV Gallup 44 47 9 May +/-2 3000 RV Reuters/Ipsos 49 42 7 May +/-3.2 959 RV Continue reading the main story

The data was collated by polling resource website Real Clear Politics. RV indicates those polled were registered voters. LV indicates a sample of likely voters.