Comparing Qualitative and Quantitative Research: A (Very) Basic Introduction
There are lots of different ways of doing research. One way of talking about these different ways is to call them 'Quantitative' and 'Qualitative'.

People who do quantitative research are usually interested in working with large groups of people. In this way they see if they can find patterns across groups of people. For example, they might look for a pattern about people's views about being gay. Then they can see if it makes a difference to your views if you are young or old. They might also be able to see what seems to cause things to happen. In order to do this work they have to find ways of measuring things. One way they do this is by using questionnaires. Another way is by doing experiments.

People who do qualitative research are interested in finding out about people's lives. They try to find out as much as they can so that the stories they hear 'make sense'. This is why qualitative researchers spend lots of time with the people they are trying to understand. Qualitative researchers also usually use interviews to get to know people. Qualitative researchers usually work with a small number of people. They try to work out why people feel the way they do.
Also see A beginner's guide to qualitative/interpretive research

