Quantitative researchers use numerical values to quantify disparity between variables to predict causal relationships and to describe characteristics of the study population. Questionnaires are structured with closed-ended questions and study designs remain rigid throughout.
In contrast, qualitative research seeks to explore responses to open-ended questions. Researchers use interviews, focus groups and participant observation in a fluid fashion, changing the course of the study along the way, according to answers given.
Both quantitative and qualitative studies make use of questionnaires and interviews, but in different ways. Quantitative questionnaires break answers into measurable quantities, and a random sample of the population is usually compared with a control group. The random sample may be stratified, that is, divided into classes according to social or other strata. In a qualitative study, broad questionnaires elicit more general responses from participants, and answers tend to be complex.
In quantitative studies, such as randomized controlled trials, or RCTs, researchers observe participants and record data numerically. In qualitative studies, researchers describe the changes they see.
A literature search is a way to collate information on a certain subject, without interviewing any new participants. Researchers review all literature on the subject, and by taking all results into account, arrive at their own conclusion.
Sometimes studies use focus groups to collect data on the cultural norms of a specific group or population. Focus groups may generate a need for further research or discussion in a certain area, or may highlight broad issues of concern in a qualitative study.
When it comes to collecting and collating your evidence, it's important to remember to write at PhD level. Writing for education website, FindAPhD.com, Professor Shahn Majid, PhD, reminds you to include a beautifully written introduction, to ensure that your referee wants to read on. Your paper should also include your motivation for the study, your methodology and results, an acknowledgement of relevant literature, anda clear and concise abstract. (See references 1)