The sensible person probably avoids them as far as possible. But we do not all behave sensibly all the time. When asked to comment on a whole range of subjects - including one's interest in books, plays, sporting events, concerts, one's intentions of buying a new car, mobile phone, and asked to specify the months in which one's house and car insurance expire, one eventually cottons on to the fact that this exercise is more for the benefit of the surveyer (surveyor?) than of the surveyee or the general public.
But there are surveys which it may be in one's own interest, or even in the public interest, to fill out. If your bank or internet provider is doing a survey on customer satisfaction, it will be to your own advantage, and to those of other customers, to let them know what they're doing right and what wrong. And if a reputable poller of public opinion (Mori, NOP) asks for your views on questions of the day, isn't it a citizen's duty to co-operate (scrupulously accurately, of course, without exaggeration or suppression of one's views, and without a thought of how they will make you look to whoever reads the answers)?
Polls are of various types: including paper, computer form or by interviewer (in person or on telephone). Some are looking for information, and some are looking for a result. The latter are generally conducted on behalf of special interest groups (I shall refrain from giving examples, because I have no wish to defend a libel action, however successfully: the reader must supply his own) and the questions are typically framed to solicit the answer sought. Where you have identified a poll of this kind, should you take part in it? If you support the special interest, perhaps you should welcome the opportunity to promote the cause (but is it honest?). If you oppose it, you may want to register your contrary view - or you may feel that you are adding credibility to the enterprise by taking part (but if you don't, someone else may).
Leave aside (for the moment) polls seeking a particular answer. What about humbler polls (on consumer products or services, for example)? Perhaps it is a civic duty to take part (if you have the time and energy). If so, you should tell the truth, the whole truth and nothing but the truth - or try to. But how? Nearly all polls are wholly or mainly multiple choice. What do you do if your choice isn't offered? Or - almost as common - you are offered several non-exclusive choices and allowed to pick only one of them? My latest experience of this was a poll offered by Eurotunnel. Generally well-organised, it offered however one question which defeated me: along the following lines: "How do you regard Eurotunnel? As a long term investment? As a risky investment? As a 'green' investment? As [something else, I forget what]? Please check one box only!". This was a paper-based poll, so I was able to ignore the instruction and tick all boxes: but online you can't do this. If you don't follow the instructions, you can't continue. In which case, should you?
Legislation (preferably Europe-wide) is urgently required to control online and telephone polling questions. This would require questions to be of three types only:
a) Questions which have the option to be answered in words the respondent chooses (eg, online, in a text box);
b) Questions that require ticking at least one and optionally more of a series of boxes. Such questions would obligatorily include as a possible response "None of the above".
c) Questions that require ticking one and only one of a series of boxes (eg by radio button, when checking one box unchecks all the others). Such questions would be obliged to include as possible answers "None of the above" and "More than one of the above".
Also, each poll would be required to include as a final question - of type (a) - "Which question in this poll did you find most irritating? Why?"
