“Qualitative research is used to explore and understand people’s beliefs, experiences, attitudes, behaviour and interactions. It generates non- numerical data, e.g. a patient’s description of their pain rather than a measure of pain. In health care, qualitative techniques have been commonly used in research documenting the experience of chronic illness and in studies about the functioning of organisations. Qualitative research techniques such as focus groups and in-depth interviews have been used in one-off projects commissioned by guideline development groups to find out more about the views and experiences of patients and carers”.
“Quantitative research generates numerical data or data that can be converted into numbers, for example clinical trials or the National Census, which counts people and households”.
“A quasi-experiment is an observational study in which the subjects to be observed are not randomly assigned to different groups in order to measure outcomes, as in a randomized experiment, but grouped according to a characteristic that they already possess”
APCRC Toolkit http://www.apcrc.nhs.uk/evaluation/documents/theoretical_approaches.pdf