Pollsters from Alpha Research and Market Links questioned voters as they left polling stations across Bulgaria on election day. Sociologists work with the data from these interviews.

Alpha Research has more than 200 interviewers, 52 of them in Sofia. They stop every third voter. On the form, people mark who they voted for, and give their sex and age. The agency chose the stations so that the sample is as representative as possible.

Sociologist Vanya Georgieva said the team works in two areas: turnout data by hour through the day, and the forms voters fill in. A small team processes what is collected in the field, even though the data covers tens of thousands of people. Statisticians, sociologists, political scientists and economists then interpret the figures.

An Alpha Research interviewer said people usually take part willingly. Voters from other stations who want to take part cannot be interviewed.

Market Links also has interviewers outside polling stations. One of them and her colleague had interviewed 127 people by 1pm. She said people stop because they know the agency, and the workload is lighter this year.

Most voters come alone and are polite, she said. Those who refuse are in a hurry, most often men whose wives are waiting downstairs with a baby.

One elderly voter asked the interviewer to sit down, then asked: "What do I do here, put a cross?" The interviewer replied: "Yes, whichever way suits you." While filling in the form, the voter said: "Here I go into the most shameful box."