Quantitative research deals with absolutes. It deals with measurable statistics - frequency, length, height, sales figures, and so on. Qualitative research deals with comparisons. Questions deal with words like better, worse, easier, etc. Quantitative asks the questions of who, what, where, and when. Qualitative asks how and why.As for which one is more valid (a qualitative question if ever there was one), it depends entirely on the topic. The key is that qualitative studies are subjective, and quantitative studies need to be objective. If you are trying to prove something true or false, a qualitative study will not do it, as opinions and researcher involvement are a major part of qualitative research, but they are quite useful for getting an opinion of the best way to do something, or most popular idea, or favorite candidate.