Even within this year’s first quarter, the uninsured rate fell consistently, from 16.2% in January to 15.6% in February to 15.0% in March. And within March, the rate dropped more than a point, from 15.5% in the first half of the month to 14.5% in the second half — indicating that enrollment through the healthcare exchanges increased as the March 31 deadline approached.
Let’s assume away the “small sample size” problem for each two week period as the entire quarter had a sample of 43,500 interviews, or an average of 3,300 a week and 6600 for each half month. This implies a margin of error of 1.2% at the 95% confidence interval.
Gallup is picking up a massive ACASurge. So from the previous peak of 18% during Q3-2013 to a presumed true uninsured rate of 14.5% or lower on April 1, 2014, that implies, again doing simple algebra, 10.8 million more people with insurance on April 1st than on average last fall.