The folks over at Politicalbetting have often examined the drawbacks of telephone polling since this method favours Labour over Tory voters. At every election, the Tory vote is usually underestimated, despite adjustments untaken by the polling firms.
The same malaise appears to have afflicted the Polish polls where the conservative 'Law and Justice' party appeared to trail Donald Tusk's 'Civic Platform'. This was due to the use of telephone polls that overestimated the votes of the urban, liberalised electorate. The right-wing conspiracists did consider a post-communist plot but the poll firms just do not appear to have considered that people without phones are capable of voting. Peter Gentle at the beetroot has the details:
The head of the company that did best in the general and presidential elections, PGB, has said that one of things they don’t do, that some of the other companies who got it so badly wrong do, is use telephone polling. Telephone polling is usually the least accurate, and in Poland, especially so. Pollsters must get a representative sample of the population they are studying, and with only 3 out of 4 Poles having access to a fixed line phone, this is not the way to find that accurate sample. PGB also said that they never do surveys in people’s homes, but always on the street.
The polish pollsters just met their '92.