Introduction[edit | edit source]
Quantitative research is a type of research that assumes that the phenomena under study can be measured and involves methods that:
- gather data using measurement (numerical data)
- analyse data by using quantitative statistical analysis techniques.
Quantitative Research Methodology[edit | edit source]
Methodology refers to the overall approach taken in a piece of research.  In quantitative research, it encompasses the general principles of investigation that guide how such a study is designed and conducted in order to answer a quantitative research question.
The methodological steps for quantitative investigations are found below.
Step 1: The Research Question[edit | edit source]
The core of any research is the research question(s).  Research question(s) guide the design and methods used in a study, being key to not only identifying gaps in knowledge but also refining and adjusting existing knowledge. 
In quantitative research, the nature of the research question may be descriptive / normative or explanatory.
Descriptive / normative research questions[edit | edit source]
Descriptive research questions provide a descriptive account of a phenomenon within an established framework of knowledge; this approach is often used when aiming to develop a fuller account of an observation and is sometimes combined with identifying some relationships of potential interest.  For example, a researcher may choose to utilise survey methods to investigate the characteristics, perceptions and behavious about a particular condition in a specific population. 
Normative research questions are similar in their purpose to descriptive research questions, but also include an additional objective of comparing data gathered with a criterion or standard. 
Explanatory research questions[edit | edit source]
Explanatory research questions usually test a hypothesis i.e. a prediction that the study sets out to either retain or reject, by means of statistical inference testing. 
Step 2: Research strategy[edit | edit source]
Quantitative investigations may be primary or secondary, depending on the source of research knowledge.
Primary research[edit | edit source]
Primary investigations involve the actual research study i.e. information gathered through self-conducted research methods. The decision on primary research is influenced by the number / quality of available information. A search for available evidence is common before any research study. Primary research study is usually based on gaps in available knowledge.
Secondary research[edit | edit source]
Secondary research accesses primary data through previously conducted quantitative research studies. Systematic reviews and meta-analyses that gather and analyse clinical/experimental primary studies rank higher than single quantitative studies in the hierarchy of evidence. 
Designs[edit | edit source]
There are two main types of primary quantitative research designs: 
Survey research designs[edit | edit source]
Survey designs are most frequently employed in healthcare epidemiology research. Surveys may be used to gain insights into opinions and practices in large samples; they can be descriptive and/or be used to test associations. 
Experimental research designs[edit | edit source]
In experimental research designs, the researcher can manipulate one (or more) variable(s), the independent variable, and study the effect on a dependent variable.  There are many types of experimental designs; one of the most important is the randomised controlled trial.
Randomised controlled trials[edit | edit source]
Randomised controlled trials are considered top methods in the hierarchy of evidence when testing the link between cause and effect in clinical interventions. 
Key differences between different forms of quantitative research[edit | edit source]
Key differences between different forms of quantitative research are found below. Distinctions have been simplified for clarity and some overlap may exist between characteristics. 
|Descriptive / Normative||Explanatory|
|Type of research||Primary||Primary|
|Nature of research question||Fairly specific and largely definite||Highly specific and definite; Declarative|
|Research design||Structured, sequential and largely predetermined||Highly structured, sequential and predetermined|
|Relationship to theory||Aims to develop or elaborate theory||Hypothesis testing|
References[edit | edit source]
- ↑ 1.0 1.1 1.2 Watson R. Quantitative research. Nurs Stand. 2015 Apr 1;29(31):44-8.
- ↑ 2.0 2.1 2.2 2.3 2.4 Sim J., Wright C. Research in Health Care: concepts, designs and methods. Nelson Thornes: Cheltenham, UK. 2002
- ↑ Mouchtouri V., Agathagelidou E., Kofonikolas K., Rousou X., Dadouli K., Pinaka O., et al. Nationwide Survey in Greece about Knowledge, Risk Perceptions, and Preventive Behaviors for COVID-19 during the General Lockdown in April 2020. Int J Environ Res Public Health. 2020 Nov 28;17(23):8854.
- ↑ Hedrick T., Bickman L., Rog D. Applied Research Design: A Practical Guide. Sage Publications, Newbury Park. 1993
- ↑ Hazra A., Gogtay N. Biostatistics Series Module 2: Overview of Hypothesis Testing. Indian J Dermatol. 2016 Mar-Apr;61(2):137-45.
- ↑ Kapoor M. Types of studies and research design. Indian J Anaesth. 2016 Sep; 60(9): 626–630.
- ↑ 7.0 7.1 Safdar N., Abbo L., Knobloch M., Seo S.Research Methods in Healthcare Epidemiology: Survey and Qualitative Research. Infect Control Hosp Epidemiol. 2016 Nov; 37(11): 1272–1277.
- ↑ Evans D. Hierarchy of evidence: a framework for ranking evidence evaluating healthcare interventions. J Clin Nurs. 2003 Jan;12(1):77-84.
- ↑ Wallace S., Barak G., Truong G., Parker M. Hierarchy of Evidence Within the Medical Literature. Hosp Pediatr. 2022 Aug 1;12(8):745-750.