Interviews enable face-to-face discussion with human subjects. If you are going to use interviews you will have to decide whether you will take notes (distracting), tape the interview (accurate but time consuming) rely on your memory (foolish) or write in their answers (can lead to closed questioning for time’s sake).
If you decide to interview you will need to draw up an interview schedule of questions which can be either closed or open questions, or a mixture of these. Closed questions tend to be used for asking and receiving answers about fixed facts such as name, numbers, and so on. They do not require speculation and they tend to produce short answers. With closed questions you could even give your interviewees a small selection of possible answers from which to choose. If you do this you will be able to manage the data and quantify the responses quite easily.
The Household Survey and Census ask closed questions, and often market researchers who stop you in the street do too. You might ask them to indicate how true for them a certain statement was felt to be, and this too can provide both a closed response, and one which can be quantified (30% of those asked said they never ate rice, while 45% said they did so regularly at least once a week... and so on).
The problem with closed questions is that they limit the response the interviewee can give and do not enable them to think deeply or test their real feelings or values.
If you ask open questions such as ‘what do you think about the increase in traffic?’ you could elicit an almost endless number of responses. This would give you a very good idea of the variety of ideas and feelings people have, it would enable them to think and talk for longer and so show their feelings and views more fully. But it is very difficult to quantify these results. You will find that you will need to read all the comments through and to categorize them after you have received them, or merely report them in their diversity and make general statements, or pick out particular comments if they seem to fit your purpose. If you decide to use interviews:
Identify your sample.
Draw up a set of questions that seem appropriate to what you need to find out.
Do start with some basic closed questions (name etc.).
Don't ask leading questions.
Try them out with a colleague.
Pilot them, then refine the questions so that they are genuinely engaged with your research object.
Contact your interviewees and ask permission, explain the interview and its use.
Carry out interviews and keep notes/tape.
Thematically analyze results and relate these findings to others from your other research methods.