Introduction to Research Studies & Research Study Types
1. Introduction to Research
Key takeaway: Research is a systematic process used to generate
new knowledge, solve problems, and answer questions.
Definition
Research is a structured, scientific investigation aimed at
discovering facts, testing theories, or solving problems. It follows a
systematic process: Identify a problem → Review literature → Choose design →
Collect data → Analyze → Interpret → Report
Purpose of Research
- Generate
new knowledge
- Improve
practice (e.g., nursing, education, public health)
- Test
interventions
- Understand
relationships between variables
- Support
evidence‑based decision‑making
2. Core Concepts
These
concepts appear in all study types.
Variables
- Independent
variable (IV): The factor manipulated or categorized
- Dependent
variable (DV): The outcome measured
Population & Sample
- Population:
Entire group of interest
- Sample:
Subset selected for study
Exposure, Outcome, Intervention
- Exposure: Any
factor influencing health or behavior
- Outcome: The
result (disease, behavior change, score)
- Intervention:
Planned exposure introduced by researchers (e.g., drug, training program)
3. Research Study Types
Research study Organized into Quantitative, Qualitative,
and Mixed‑Methods, then Experimental vs. Observational.
A. Quantitative Study Designs
Focus on numbers, measurement, and statistical analysis.
1. Experimental Studies (Strongest evidence for causation)
Researchers manipulate the independent variable and randomly
assign participants.
Randomized Controlled Trial (RCT)
- Participants
randomly assigned to intervention vs. control
- Best
for determining cause and effect
- Used
in clinical trials, education interventions
Quasi‑Experimental
- Intervention
present
- No
random assignment
- Used
when randomization is not possible (e.g., classroom groups)
2. Observational Studies (No manipulation)
Researchers observe natural exposures.
Cross‑Sectional Study
- Snapshot
at one point in time
- Measures
prevalence
Case‑Control Study
- Start
with outcome (cases) vs. no outcome (controls)
- Look
backward at exposure history
- Good
for rare diseases
Cohort Study
- Follow
participants over time
- Compare
exposed vs. non‑exposed
- Shows
incidence and risk
Longitudinal Study
- Repeated
measures over time
- Tracks
change or development
3. Other Quantitative Designs
- Descriptive
studies: Describe characteristics or frequency
- Correlational
studies: Measure relationships (no causation)
B. Qualitative Study Designs
Focus on experiences, meanings, and perspectives.
Common Qualitative Designs
- Case
Study: In‑depth exploration of one case
- Phenomenology:
Lived experiences
- Ethnography:
Cultural immersion
- Grounded
Theory: Build theory from data
Data Collection Tools
- Interviews
- Focus
groups
- Observations
- Document
analysis
C. Mixed‑Methods Studies
Combine quantitative + qualitative to
provide a richer understanding.
Examples:
- Qualitative
interviews + quantitative surveys
- RCT
with qualitative feedback
4. Criteria for Choosing a Study Type
Match the design to:
1. Research Question
- Cause
and effect? → Experimental
- Association? →
Observational
- Experience
or meaning? → Qualitative
- Complex
problem? → Mixed‑methods
2. Ethical & Practical Constraints
- Can
you randomize?
- Is
the outcome rare? (→ Case‑control)
- Do
you need long follow‑up? (→ Cohort)
3. Resources & Time
- Cross‑sectional
= fast
- Cohort
= long and expensive
- RCT
= requires strict control
5. Tools & Software for Research
Quantitative Tools
- SPSS
- R
- Stata
- Excel
Qualitative Tools
- NVivo
- ATLAS.ti
- MAXQDA
Mixed‑Methods
- MAXQDA
- NVivo
6. Conclusion
Research design determines what conclusions you can make. Experimental
designs show causation; observational designs show association; qualitative
designs explore meaning.
Encourage students to:
- Choose
design based on the research question
- Understand
strengths and limitations
- Apply
ethical principles
- Use
appropriate tools and software
References
1. Creswell JW, Creswell JD. Research
Design: Qualitative, Quantitative, and Mixed Methods Approaches. 5th ed. Thousand Oaks (CA): SAGE Publications;
2018.
2. Polit DF, Beck CT. Nursing
Research: Generating and Assessing Evidence for Nursing Practice. 11th ed. Philadelphia (PA): Wolters Kluwer; 2021.
3. Grove SK, Gray JR, Burns N. Understanding
Nursing Research: Building an Evidence‑Based Practice. 7th ed. St. Louis (MO): Elsevier; 2019.
4. Hulley SB, Cummings SR, Browner
WS, Grady DG, Newman TB. Designing Clinical Research. 4th ed. Philadelphia (PA): Lippincott Williams
& Wilkins; 2013.
5. Greenhalgh T. How to
Read a Paper: The Basics of Evidence‑Based Medicine and Healthcare. 6th ed. Hoboken (NJ): Wiley‑Blackwell; 2019.
6. Thiese MS. Observational
and Interventional Study Design Types; An Overview. Biochem Med (Zagreb). 2014;24(2):199‑210.
7. Mann CJ. Observational research
methods. Research design II: cohort, cross‑sectional, and case‑control
studies. Emerg Med J. 2003;20(1):54‑60.
8. Kothari CR. Research
Methodology: Methods and Techniques. 2nd
ed. New Delhi: New Age International; 2004.
9. Patton MQ. Qualitative
Research & Evaluation Methods. 4th ed.
Thousand Oaks (CA): SAGE Publications; 2015.
10. Tashakkori A, Teddlie C. Mixed
Methodology: Combining Qualitative and Quantitative Approaches. Thousand Oaks (CA): SAGE Publications; 1998.