Afghanistan Poll: Note on Methodology

This survey was conducted for ABC News, the BBC and ARD by Charney Research of New York, with field work by the Afghan Center for Social and Opinion Research, based in Kabul. Interviews were conducted in person, in Dari or Pashto, among a random national sample of 1,377 Afghan adults from Oct. 28 to Nov. 7.

A total of 176 sampling points were distributed, proportional to population size in each of Afghanistan's 34 provinces, stratified by urban/nonurban status. Sampling points were then distributed to randomly selected districts within provinces, also proportionate to population size; and lastly, to randomly selected villages or neighborhoods within those districts, by simple random sampling.

Sources for population parameters were United Nations population estimates and population projections from the Afghan Central Statistics Office.

Half the sampling points were designated for male interviews, half for female interviews. Male respondents were interviewed only by male interviewers, female respondents only by female interviewers. Residences were selected within each settlement by random route/random interval, and respondents were selected within residence by Kish grid.

In addition to the national sample, oversamples were drawn in Nangerhar, Helmand, Kandahar, Herat, Balkh and Kunduz provinces, to allow for more reliable analysis in those areas. The national sample was weighted by population of province to adjust for the oversample.

In order to reduce the design effect due to clustering, where randomly drawn male/female sampling points fell within close proximity to each other, in districts with fewer than 20,000 residents, the number of sampling points was doubled, also by random selection, and the number of interviews per point was halved, from 10 to five. Of the total of 176 sampling points, 78 were assigned in this manner.

Interviews were conducted by 161 interviewers in 34 supervised teams. All interviewers were trained, and all but three had experience on previous ACSOR surveys. Eleven percent of interviews were directly observed by field supervisors, and an additional 13 percent were back-checked afterwards, with further logical controls conducted at ACSOR offices in Kabul.

The survey had a contact rate of 93 percent, and a cooperation rate of 95 percent, for a net response rate of 89 percent. The impact of clustering on the sample produces an estimated design effect of 1.22, for a total margin of sampling error of 3 percentage points at the 95 percent confidence level.