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📚 Research Methodology & Article Writing - Easy Notes
(Based on CPSP Research Evaluation Unit Reading Material)
📌 CHAPTER 1: Introduction to Research
Research = A systematic, scientific process of collecting, analyzing, and interpreting data to find solutions to a problem.
Types of Research
| Type | What it does | Example |
|---|
| Quantitative | Collects measurable data using closed-ended questions; uses statistics | Survey asking "Rate your pain 1-10" |
| Qualitative | Explores the why behind things through interviews, focus groups | Asking doctors "Why do patients skip follow-ups?" |
| Mixed Methods | Combines both | Study using a survey + in-depth patient interviews |
Key Terms
- Research Objective - What the researcher clearly intends to find out. (e.g., "To determine the prevalence of diabetes in adults aged 40-60 in Karachi")
- Rationale - Why this study? What gap does it fill? What was wrong or missing in previous studies?
- Operational Definition - Exactly how you will measure your variables. (e.g., "Hypertension = BP ≥140/90 on two separate readings")
- Literature Search - Systematically searching journals, conference papers, and databases to understand what's already known before starting your research.
📌 CHAPTER 2: Types of Study Designs
Think of study designs as your "plan of attack" for answering a research question.
1. Descriptive Studies (Describe what's happening - no hypothesis)
| Design | Description | Example |
|---|
| Case Report | 1 unusual/rare case | A single patient with a never-seen-before drug reaction |
| Case Series | Several similar unusual cases | 5 patients who all developed the same rare syndrome |
| Cross-Sectional | Snapshot of a population at one point in time (= prevalence study) | Survey 1,000 people today to check who has obesity |
| Clinical Audit | Reviews current practice against set standards to improve care | Checking if 95% of heart attack patients received aspirin within 1 hour |
| Longitudinal | Follows the same people over years | Tracking 500 children from birth to age 18 |
2. Analytical Studies (Test a hypothesis - always have 2+ groups)
Observational (researcher watches, doesn't intervene)
| Design | Direction | Example |
|---|
| Cohort (Prospective) | Exposure → follow forward → Outcome | Follow smokers & non-smokers for 20 years to see who gets lung cancer |
| Cohort (Retrospective) | Look backward using old records | Use hospital records: who was exposed to asbestos, did they get mesothelioma? |
| Case-Control | Start from Outcome → look back at Exposure | Take 100 lung cancer patients (cases) + 100 healthy people (controls) → compare their smoking history |
Memory trick: Cohort = forward in time (cause → effect). Case-Control = backward (effect → cause).
Experimental (researcher assigns exposure)
| Design | Description | Example |
|---|
| RCT | Randomly assign participants to treatment or control group | Randomly give half the patients Drug A, half a placebo; see who gets better |
| Non-randomized (Quasi-experimental) | Participants choose or are assigned without random chance | Patients who volunteer for a new diet program vs. those who don't |
| Preventive Trial | Test ways to prevent disease | Testing a new vaccine on healthy people |
| Therapeutic Trial | Test new treatments for existing disease | Testing a new chemo drug on cancer patients |
Blinding Types
| Type | Who is Blind? |
|---|
| Single-blind | Participant only |
| Double-blind | Participant + Researcher |
| Triple-blind | Participant + Researcher + Data Analyst |
Why blind? To prevent bias in results. (e.g., if you know you're getting the real drug, your pain might "feel better" due to psychology - the placebo effect)
Placebo = An inactive substance (like a sugar pill) given to the control group so they don't know they're not getting the real treatment.
📌 CHAPTER 3: Sampling
What is a Sample?
A sample is a smaller group taken from the full population. We study the sample to make conclusions about the whole population.
Example: Instead of testing all 200 million Pakistanis, you test 400 people representing the whole country.
Sampling Techniques
1. Probability Sampling (everyone has an equal chance - statistically valid)
| Technique | How it works | Example |
|---|
| Simple Random | Use a lottery or random number table | Draw 100 names from a list of 1,000 patients |
| Systematic | Pick every K-th person (K = population ÷ sample size) | If K=10, pick patient #10, #20, #30... |
| Stratified | Divide into groups (strata), then randomly sample each | 50 men + 50 women, or by age group |
| Cluster | Divide area into clusters; randomly pick clusters | Randomly select 5 hospitals out of 20, then study all patients in those 5 |
2. Non-Probability Sampling (not statistically ideal, but practical)
| Technique | How it works | Example |
|---|
| Convenience | Take whoever is easily available | Survey patients waiting in your clinic today |
| Consecutive | Take every patient meeting criteria over a set time - best non-probability method | Enroll every diabetic patient admitted in 6 months |
| Snowball | Existing participants recruit others | Recruit drug users; each refers others in their network |
| Purposive | Select specific targets based on knowledge | Interview only senior surgeons about a rare procedure |
📌 CHAPTER 4: Variables, Data & Presentation
Variables
- Dependent Variable = The OUTCOME you're measuring. (e.g., blood sugar level, death, recovery)
- Independent Variable = The CAUSE or EXPOSURE you think influences the outcome. (e.g., diet, smoking, drug type)
Example: Studying if smoking causes lung cancer → Smoking = independent variable; Lung cancer = dependent variable.
Types of Data
DATA
├── QUALITATIVE (categories)
│ ├── Nominal - No order (e.g., blood group: A, B, O, AB; gender: M/F)
│ └── Ordinal - Has order but no fixed distance (e.g., cancer stage I, II, III, IV; pain scale: mild/moderate/severe)
│
└── QUANTITATIVE (numbers)
├── Discrete - Whole numbers only (e.g., number of children: 0, 1, 2, 3)
└── Continuous - Any value, including decimals (e.g., weight: 65.4 kg, height: 170.2 cm)
How to Present Data
| Data Type | Best Presentation |
|---|
| Qualitative (categories) | Frequency table, Pie chart, Bar chart |
| Quantitative (numbers) | Histogram (like bar chart but no gaps between bars) |
Pie chart example: 60% of patients are male, 40% female - shown as slices of a circle.
Histogram example: Distribution of patient ages - shows if data is normally distributed.
📌 CHAPTER 5: Summarization of Data
Measures of Central Tendency (Where is the "middle"?)
| Measure | Definition | Example (data: 2, 3, 3, 5, 7) |
|---|
| Mean | Sum ÷ number of values | (2+3+3+5+7) ÷ 5 = 4 |
| Median | Middle value after sorting | Sorted: 2,3,3,5,7 → 3 |
| Mode | Most frequent value | 3 (appears twice) |
Measures of Variation (How spread out is the data?)
| Measure | Definition | Example |
|---|
| Range | Largest - Smallest | 7 - 2 = 5 |
| Variance (S²) | Average of squared deviations from mean | Tells how much values vary |
| Standard Deviation (SD) | Square root of variance | If mean height = 170 cm, SD = 5 means most people are between 165-175 cm |
Key insight: Small SD = data points are close together. Large SD = data is spread widely.
Standard Error & Confidence Interval
- Sampling Variation - Every sample you take will give slightly different results - this is natural.
- Standard Error (SE) - Estimates how much your sample mean might differ from the true population mean.
- Confidence Interval (CI) - A range within which the true value likely falls.
Example: "The mean blood pressure is 130 mmHg (95% CI: 125-135)" means you are 95% sure the true population mean is between 125-135 mmHg.
Normal Distribution (Bell Curve) - Most values cluster around the mean, with fewer values at the extremes (tails).
📌 CHAPTER 6: Estimation & Hypothesis Testing
Hypothesis
- Null Hypothesis (H₀) = "There is NO difference/relationship." (e.g., "Drug A and Drug B have the same effect")
- Alternate Hypothesis (H₁) = "There IS a difference/relationship." (e.g., "Drug A is better than Drug B")
P-Value
- P-value = Probability that your result occurred by chance if H₀ were true.
- If p ≤ 0.05 → Result is statistically significant → Reject H₀ (accept H₁)
- If p > 0.05 → Do NOT reject H₀
Example: p = 0.02 means there's only a 2% chance your result was due to chance - so your finding is likely real!
Errors in Hypothesis Testing
| Error | What Happened | Example |
|---|
| Type I (Alpha error) | You said there's a difference, but there isn't | You conclude Drug A is better - but it's not |
| Type II (Beta error) | You said there's no difference, but there is | You conclude drugs are equal - but Drug A is actually better |
- Power = Probability of correctly detecting a real difference = 1 - Beta. Higher power = better study.
📌 CHAPTER 7: Measures of Disease Frequency
Prevalence vs. Incidence
| Measure | What it counts | Formula | Example |
|---|
| Point Prevalence | Existing cases at one point in time | Current cases ÷ Total population at that time | On Jan 1, 50 out of 1,000 people have TB = 5% |
| Period Prevalence | Cases over a time period | Cases during period ÷ Average population | TB cases during all of 2024 |
| Incidence | NEW cases developing in a time period | New cases ÷ Population at risk | 20 new TB cases per 1,000 people per year |
Memory trick: Prevalence = existing (like a photograph). Incidence = new (like a video recording new events).
📌 CHAPTER 8: Measures of Association
Correlation Coefficient (r)
- Measures the relationship between two variables
- Ranges from -1 to +1
- +1 = perfect positive correlation (both go up together)
- -1 = perfect negative correlation (one goes up, other goes down)
- 0 = no relationship
Relative Risk (RR) - Used in Cohort Studies
RR = Incidence in Exposed ÷ Incidence in Unexposed
| RR Value | Meaning |
|---|
| RR = 1 | No association |
| RR > 1 | Exposure increases risk |
| RR < 1 | Exposure is protective |
Example: Smokers develop lung cancer at 15%, non-smokers at 1% → RR = 15/1 = 15 (smokers are 15x more likely to get lung cancer)
Odds Ratio (OR) - Used in Case-Control Studies
OR = (a × d) ÷ (b × c) using a 2×2 table
- Used when you cannot calculate incidence (because you started with diseased people)
- Interpretation same as RR: OR > 1 = increased risk
📌 CHAPTER 9: Bias, Confounding & Effect Modification
Bias = Systematic error that distorts your results
| Type | What it is | Example |
|---|
| Selection Bias | Wrong people enrolled | Studying hospital patients to draw conclusions about the general population |
| Recall Bias | People remember past exposures differently | Cancer patients remember smoking more clearly than healthy people |
| Interviewer Bias | Interviewer's manner influences answers | Interviewer nods when patient says "yes" to symptoms |
| Lost to Follow-up Bias | Patients drop out before study ends | Sicker patients drop out, making drug look better than it is |
How to control bias: Blinding, standardized data collection tools, proper questionnaires, careful choice of study population.
Confounding
A confounder is a third variable that is linked to both the exposure and the outcome, distorting the apparent relationship.
Classic Example: Studies find coffee drinkers get more lung cancer. But coffee drinkers also tend to smoke more. Smoking is the confounder - not the coffee!
Control confounding by:
- At design stage: Restriction, Matching, Randomization
- At analysis stage: Stratification, Multivariate Analysis
Effect Modifier
A variable that changes the strength of the relationship between exposure and outcome in different subgroups.
Example: A drug works well in women but not men - gender is an effect modifier.
📌 CHAPTER 10: Sample Size Calculation
Sample size = how many participants you need for your study to be valid and reliable.
What you need to calculate sample size:
| Descriptive Studies | Analytical Studies |
|---|
| Prevalence/mean±SD from previous studies | Outcome magnitude for BOTH groups |
| Level of significance | Level of significance |
| Margin of error (d) | Power of the test |
Key Terms
- Significance Level = Risk of a false positive (usually 5% = 0.05)
- Margin of Error (d) = How much deviation from the true prevalence you can tolerate (e.g., ±5%)
- Power = Ability to detect a real difference (usually 80-95%). More power = larger sample needed.
📌 CHAPTER 11: Screening Tests
The 2×2 Table
Disease + Disease -
Test Positive | a (TP) | b (FP) |
Test Negative | c (FN) | d (TN) |
| Measure | Formula | Meaning |
|---|
| Sensitivity | a ÷ (a+c) × 100 | How good is the test at finding sick people? (True positive rate) |
| Specificity | d ÷ (b+d) × 100 | How good is the test at clearing healthy people? (True negative rate) |
| PPV | a ÷ (a+b) × 100 | If test is positive, what's the chance the person actually has the disease? |
| NPV | d ÷ (c+d) × 100 | If test is negative, what's the chance the person is truly disease-free? |
Example: HIV ELISA has high sensitivity (>99%) - catches almost all HIV+ people. Confirmatory Western Blot has high specificity - rules out false positives.
Memory trick: SN-out (Sensitive test, if Negative → rules OUT disease). SP-in (Specific test, if Positive → rules IN disease).
📌 CHAPTER 12: Questionnaire Development
Types of Questions
| Type | Description | Example |
|---|
| Closed-ended | Pre-set answer choices; used in quantitative research | "Do you smoke? Yes / No" |
| Open-ended | Free-text answers; used in qualitative research | "Describe your pain experience" |
Likert Scale
Used to measure abstract concepts like quality of life, satisfaction, or attitudes.
Example: "The doctor explained my condition clearly."
Strongly Agree | Agree | Neutral | Disagree | Strongly Disagree
📌 CHAPTER 13: Bioethics
The 4 Core Principles
| Principle | Meaning | Example |
|---|
| Autonomy | Respect patient's right to decide | Patient refuses surgery - you must respect that |
| Beneficence | Do good for the patient | Giving pain relief to a suffering patient |
| Non-maleficence | Do no harm | Avoiding unnecessary surgery |
| Justice | Fairness in resource distribution | Equal ICU access during a pandemic |
Ethical Considerations in Research
- Informed Consent - Participants must know the purpose, risks, and benefits before agreeing
- No Plagiarism - Give credit, cite sources properly
- Conflict of Interest - Disclose any financial or personal ties to the research
- Data Confidentiality - Keep participant data secure
- Animal Welfare - Follow ethical guidelines when using animals
Consequences of Unethical Research
- Retraction of published papers
- Loss of credibility and public trust
- Legal action and professional penalties
- Inability to replicate findings
📌 CHAPTER 14: Publishing Original Research
IMRaD Structure (The Standard Format)
| Section | What to Include |
|---|
| Introduction | Background, rationale, research objective |
| Methods | Study design, ethics approval, population, data collection, analysis plan |
| Results | Present findings using tables and figures |
| and Discussion | Interpret results, compare with past studies, state limitations |
| + Conclusion | Summary and implications |
Key Qualities of a Good Research Article
- Novelty - New findings, not published before
- Scientific Rigor - Clear hypothesis, valid methods
- Ethical Approval - Mandatory for human/animal studies (ERC/IRB)
- Reproducibility - Methods described in enough detail for others to replicate
Reporting Guidelines by Study Design
| Study Type | Guideline |
|---|
| RCT | CONSORT |
| Cohort/Case-Control/Cross-sectional | STROBE |
| Systematic Review/Meta-analysis | PRISMA |
| Qualitative studies | COREQ |
| Diagnostic accuracy | STARD |
| Case reports | CARE |
| Animal studies | ARRIVE |
Publishing Process (Step-by-Step)
- Develop a clear research question
- Get Ethics Committee (ERC/IRB) approval
- Register the trial (if it's a clinical trial)
- Follow the relevant guideline (CONSORT, STROBE, etc.)
- Get synopsis approved by REU (CPSP)
- Conduct the study
- Write with clarity and scientific integrity
- Submit to a peer-reviewed, indexed journal (as per HEC/CPSP criteria)
🧠 Quick Summary Table
| Chapter | Core Concept | One-line Memory Aid |
|---|
| 1 | Research types | Quant = numbers; Qual = why; Mixed = both |
| 2 | Study designs | Descriptive = describe; Analytical = test; Experimental = intervene |
| 3 | Sampling | Probability = equal chance; Non-probability = convenient |
| 4 | Variables & data | Dependent = outcome; Independent = cause |
| 5 | Data summary | Mean/Median/Mode = center; SD = spread |
| 6 | Hypothesis testing | p < 0.05 = significant; Type I = false alarm; Type II = missed call |
| 7 | Disease frequency | Prevalence = existing; Incidence = new |
| 8 | Association | RR for cohort; OR for case-control |
| 9 | Bias & confounding | Bias = error; Confounder = hidden 3rd variable |
| 10 | Sample size | Need significance level + power + expected prevalence |
| 11 | Screening | Sensitivity = find sick; Specificity = clear healthy |
| 12 | Questionnaire | Closed = quantitative; Open = qualitative; Likert = scale |
| 13 | Bioethics | Autonomy, Beneficence, Non-maleficence, Justice |
| 14 | Article writing | IMRaD format + right reporting guideline |