There are many types of ‘bad’ questions but two types we want to highlight are leading questions and combined feature questions.
A leading question is one where the respondent is potentially directed towards to a particular response. A blatant (hypothetical) example might be “Do you love your children enough to give them Colgate toothpaste?”. This suggests that if you don’t buy Colgate toothpaste you don’t love your children, when these two things should be unrelated.
Beware questions, popular amongst journalists, that begin “Do you agree that…”
A combined feature question is where two (or more) different elements are contained in a single question. For example, “Provide up to minute information on share prices and exchange rates” combines two different categories of information – shares and exchange rates. If the respondent thinks they are good at one but poor at the other how do they respond and how would one interpret this response?
The key is presenting questions in a neutral way and providing clarity on what one is asking.