These are questions that have no suggested answers and give people the oppourtunity to reply as they wish. Eg. "what did you do today?"
Open questions are good because they allow the person being questioned to give detailed and informative answers.
A disadvantage of using open questions is that there is a wide range of responses, which makes it hard for the answers to be compared and analysed.
These are questions which give a set of answers for the person to choose from. Like tick boxes in a written questionnaire.
An advantage of this is that it restricts the response, making it easier for the answers to be collated and analysed.
A disadvantage of using closed questions is that it may not include the response that somebody wants to give, and the data that scollected lacks detail.
Pilot survey (pre-test)
This is a small scale replica of the survey thats carried out to ensure that the method of data collection is suitable to be used in the actual survey.
These are questions that influence the person to give a certain answer. People should avoid asking leading questions when conducting an interview, as they may affect the results.