Questionnaires have advantages over some other types of surveys in that they are cheap, do not require as much effort from the questioner as verbal or telephone surveys, and often have standardized answers that make it simple to compile data.Usually, a questionnaire consists of a number of questions that the respondent has to answer in a set format. A distinction is made between open-ended and closed-ended questions. An open-ended question asks the respondent to formulate his own answer, whereas a closed-ended question has the respondent pick an answer from a given number of options.Use statements which are interpreted in the same way by members of different subpopulations of the population of interest.
Use statements where persons that have different opinions or traits will give different answers.
Think of having an "open" answer category after a list of possible answers.
Use only one aspect of the construct you are interested in per item.