uni'wissen 01(3)-2011_ENG

­Education of Baden-Württemberg helped them present the results of the opinion poll to the pub- lic with a podium discussion, several newspaper articles, and a project homepage. The first challenge for the students was to ­develop the questionnaire. The trick was to find relevant questions and formulate them as pre- cisely and impartially as possible. “The quality of the questionnaire is the pivotal factor. We thus discussed every question many times over,” says Wagschal. The students studied opinion polls conducted by the polling institute Forschungs- gruppe Wahlen from the 1960s to the present, evaluated and improved their own list of ques- tions in over 25 rounds with test subjects, and had the list analyzed by professional pollsters. The poll collected data on more than 100 vari- ables: What do you consider to be the most im- portant problem currently facing Baden-Würt- temberg? Who would you like to see as the state’s minister president? And, particularly im- portant for the media and the public, the tradi- tional question of the weekly political opinion polls released each Sunday in Germany: What party would you vote for if elections were to take place next Sunday? Chance as a Statistical Principle The participants were selected randomly, thus ensuring that the poll would reach a representa- tive cross-section of society. The basis for selec- tion was a so-called “mother sample” of 7,000 telephone numbers. An electronic random num- ber generator varied the last digit of the numbers to ensure that numbers not included in the tele- phone book were also represented. The member of each household who had most recently cele- brated his or her birthday was chosen to ­participate in the poll. “If we had just chosen the person who answered the phone, we would have interviewed the daughter of the house too often,” explains Wagschal. The students called 31,000 numbers and reached a total of 11,000 citizens; 1,361 of the persons called ended up participating. For the 25 young researchers who conducted the poll, this meant up to 120 at- tempts per day over a period of three weeks starting in late January. An average of only six to seven of these attempts were successful. Many of the people who answered the phone hung up immediately, some vented their anger about the state of politics, and others agreed to participate. The researchers were forced to react to these situations, sometimes with appeals to reason, sometimes with appeals to the emotions. Wag- schal believes that this communication process was the most important experience for the stu- dents: “The students saw how heterogeneous the state is. Freiburg is not the world.” The Trade Secret of Opinion Researchers The data was made anonymous and weighted for the analysis. This means that not all of the responses were treated equally. Along with the development of the questionnaire, this is one of the most important factors in a scientifically sound analysis, says Wagschal and it is also a source of possible criticism: Many opinion re- search institutes have a reputation for being ­biased toward a particular party or for slanting results to satisfy their clients. “Opinion research- ers never reveal their weighting methods; that’s their big trade secret.” The students experiment- ed with various values and watched how they changed the results. “We put a lot of thought into how to best weight the data. That was the key to our success.” Data collection is hard work: Conducting the telephone interviews was the most important experience for the students. Photo: Kunz “The students saw how heterogeneous the state is. Freiburg is not the world” 10 uni'wissen 03