Research Design Overview

This note consolidates key concepts from four PDF resources, offering a concise guide to research participants, health research fundamentals, essential planning questions, and comprehensive design and synthesis methods for health studies.

Section 1: Research Foundations & Health Study Design 🧬

This section covers foundational research principles, health research frameworks, and study design methodologies from a 45-page PDF presentation (source).

1.1 Research Fundamentals

Definition of Research:

"The systematic and careful investigation of a subject to discover new insights about the world."

Five-Step Research Process:

Step	Description
1	Identify a study question
2	Select a general study approach
3	Design the study and collect data
4	Analyze data
5	Write and share a report

1.2 Health Research Scope

Health Research Definition:

Examines a broad spectrum of biological, socioeconomic, environmental, and other factors that influence physical, mental, and social health and well-being.

Population Health Research:

When the unit of investigation is a human population, the work is termed population health research.

1.3 Purposes of Health Research

To understand various dimensions of health, identify problems, and provide data for health policy making and interventions.

1.4 Topic Selection & Frameworks

Sources of Research Questions:

Clinical practice observations.
Community observations.
Personal experience.

Topic Narrowing Example:

U.S. Obesity → Pediatric Obesity → Risk Factors → Cognitive Functions → Self-regulation Skills.

EDP Framework:
Describes the purpose of health research and typical applications:

Purpose	Typical Application
Needs assessment	Community health profiles that identify gaps in services.
Risk assessment	Identification of risk factors for disease (e.g., smoking, obesity).
Applied practice	Evaluation of clinical effectiveness of interventions.
Outcomes evaluation	Measurement of the impact of public-health programs or policies.

1.5 Evidence Sources & Critical Appraisal

Source Types:

Element	Definition
Exposure	The factor that might influence health (e.g., diet, air pollution).
Disease/Outcome	The health condition or result of interest (e.g., diabetes).
Population	The group being studied (e.g., adolescent girls).

PICOT for Clinical Research:

Letter	Meaning
P	Patient/Population: Who is being studied?
I	Intervention: What is being done?
C	Comparison: What is the alternative?
O	Outcome: What is measured?
T	Timeframe: Over what period?

Category Descriptions:

Category	Description
Informal sources	Non-technical material from trusted agencies (CDC, WHO). Useful for background but not peer-reviewed.
Statistical reports	Large-scale data sets (World Bank, UN agency reports, CDC, American Cancer Society, state/local health departments).
Research abstracts	Concise (~250-350 words) summaries of articles, either unstructured or structured (Background, Aim, Methods, Results, Conclusions).

Critical Appraisal Criteria:

Internal Validity: How well the study was designed, conducted, interpreted, and reported.
External Validity: Applicability of findings to other populations.
Originality: Study introduces at least one substantive difference from prior work (new exposure, disease, population, or perspective).

1.6 Study Approaches & Frameworks

Study Approach Types:

Approach	What It Involves
Primary study	Collects new data directly from individuals (e.g., surveys, experiments).
Secondary study	Analyzes existing data sets (e.g., national health surveys, electronic health records).
Tertiary study	Reviews existing literature (systematic reviews, meta-analyses).

Framework Types:

Framework: Purpose
- Conceptual framework: Illustrates key relationships among the EDP elements to be evaluated. It is idea-based and often developed by the researcher.
- Theoretical framework: Draws on established models from the literature to explain those relationships. It is evidence-based.

1.7 Study Goals & FINER Criteria

Worked Example (College-Student Nutrition):

Main Study Goal: Examine the associations between interoception, self-regulation, purposeful and non- purposeful eating domains, and BMI in college students.
Aim #1: Individuals with high interoceptive sensibility will have higher self-regulation, purposeful eating behaviors, and a healthy BMI.
Aim #2: Individuals with reduced interoceptive sensibility will have reduced self-regulation, higher non-purposeful eating behaviors, and an overweight/obese BMI.

FINER Criteria:

Types of Feasibility Assessment Criteria:

Feasible: Resources, time, expertise, and access are realistic.
Interesting: The question engages the researcher and the broader community.
Novel: The study adds new knowledge (see originality criteria).
Ethical: All procedures protect participants and comply with regulations.
Relevant: Findings will have practical or theoretical importance.

Section 2: Exam Preparation & Study Design Mastery 📚

This section provides a comprehensive exam review guide covering research concepts, study designs, and methodological considerations from a 1-page PDF document (source).

2.1 Research Overview - Key Knowledge Areas

Health Research Purposes:

The various aims that drive health-related investigations including needs assessment, risk assessment, applied practice, and outcomes evaluation.
Goal of a 'Need Assessment': Identify gaps in services or health outcomes.

Exposure, Disease, Population (EDP):

The three-component framework that links an exposure, a disease outcome, and the population under study.

Internal vs. External Validity:

Type	Definition
Internal Validity	Concerns the study's internal rigor and whether conclusions truly reflect results.
External Validity	Concerns the generalizability of findings to other populations.

Study Approaches:

Primary: Original data collection.
Secondary: Analysis of existing data.
Tertiary: Synthesis of secondary evidence.

Conceptual and Theoretical Frameworks:

The scaffolding used to guide study development: a conceptual model (often visual) and a formal theoretical model situates the study within existing theory.

FINER Criteria Letter Meanings:

Letter	Meaning
F	Feasible
I	Interesting
N	Novel
E	Ethical
R	Relevant

2.2 Introduction & Background Requirements

Defining a Research Question:

How to formulate a clear, focused question that guides the study - must end in a question mark and be testable.

Introduction Structure:

The logical organization including opening statement, context, gap identification, and purpose statement.

Literature Review Elements:

Scope of existing research.
Relevance to current study.
Synthesis of findings.
Identification of gaps.

Citation Requirements:

Proper formatting and completeness for all sources within the introduction/background.

2.3 Study Designs - Comprehensive Coverage

Core Study Designs to Master:

Cohort studies.
Case-control studies.
Cross-sectional studies.
Randomized controlled trials (RCT).
Ecological studies.

Key Design Features:

Matching Definitions: The concept of matching participants (or units) on certain variables to control confounding.
Study Design Considerations/Limitations: Strengths, weaknesses, and situational appropriateness of each design.
Analyses for Each Study Design:
- Logistic regression for case-control.
- Survival analysis for cohort.
- Appropriate statistical methods for each design type.

Randomization Types:

Simple randomization.
Block randomization.
Stratified randomization.

Specificity vs. Sensitivity:

Sensitivity: The true-positive rate.
Specificity: The true-negative rate.
Trade-offs between these diagnostic test properties.

Ecological Fallacy:

The error of inferring individual-level relationships from aggregate data.

Systematic Reviews & Meta-analyses:

The process of systematically collecting, appraising, and quantitatively synthesizing results from multiple studies.

2.4 Key Relationships & Patterns

Relationship	Implication
Need assessment → Study Goals/Objectives	A need assessment helps define the precise goals and objectives of a project.
EDP ↔ Study Designs	Every design must specify the exposure, disease, and population it will investigate.
Validity (internal/external)	Underpins credibility of primary, secondary, and tertiary approaches.
Matching ↔ Control of Confounding	Matching is a design technique used to reduce confounding bias.
Randomization types ↔ Internal Validity	Proper randomization enhances internal validity.
Specificity/Sensitivity ↔ Design choice	Certain designs focus on these parameters.
Ecological Fallacy ↔ External Validity	Recognizing this fallacy helps judge external validity.
Systematic reviews & meta-analyses ↔ Tertiary study approach	They synthesize secondary evidence, representing the highest level of evidence hierarchy.

Section 3: Research Planning & Proposal Development 🎯

This section explores the four prerequisite planning questions, literature review processes, and scholarly writing guidelines from a 15-page presentation (source).

3.1 Four Prerequisite Planning Questions

Key Questions & Importance:

Question	Why it matters
1	What is the one well-defined research question that the study will answer?
2	What specific aims, objectives, or hypotheses will enable the key question to be answered?
3	Would a conceptual framework be helpful for guiding the design, analysis, and interpretation of the study and its results?
4	Is the proposed study feasible? Is there a high likelihood that the research team will be able to answer the study's main research question?

3.2 Conducting a Literature Review

Purpose of the Review:

A literature review is a "re-viewing" of what reputable scholars in the field have said, done, and found.
Objectives include surrounding the proposed study within the existing body of knowledge, identifying research gaps that the new study can address.

Tools & Formats:

Annotated bibliography: A systematic record that pairs each citation with a concise summary and critical evaluation.
Proposal Application #1: Indicates that the annotated bibliography can serve as a preliminary deliverable.

3.3 Types of Purpose Statements

Purpose Statement Type	Typical Research Focus
Argument	Persuade the reader of a particular stance.
Evaluation	Assess the effectiveness or quality of a program, policy, etc.
Analysis	Break down a phenomenon into its constituent parts.
Comparison	Contrast two or more entities, conditions, or groups.
Cause and Effect	Examine causal relationships.

3.4 Example Study: Interoception, Self-Regulation, Eating Behaviors, and BMI

Main Goal:

"Examine the associations between interoception, self-regulation, purposeful and non-purposeful eating domains, and BMI in college students."

Specific Aims:

Implicit Conceptual Framework: A mediational framework where interoceptive sensibility influences self-regulation, which in turn shapes eating behavior (purposeful vs. non-purposeful), culminating in BMI outcomes.

3.5 Scholarly Voice & Writing Guidance

UCF Writing Center's "Scholarly Voice" Guidelines:

Use formal, objective language reflecting academic standards.
Maintain clarity and conciseness while presenting complex ideas.
Cite credible, peer-reviewed sources throughout the literature review and rationale.

Purpose Statement Type & Expected Relationship Direction:

Aim	Statement	Expected Direction of Relationship
Aim 1	Individuals with high interoceptive sensibility will have higher self-regulation, purposeful eating domain behaviors, and healthy BMI status.	Positive interoception → ↑ self-regulation & purposeful eating → healthier BMI.
Aim 2	Individuals with reduced interoceptive sensibility will have reduced self-regulation, higher non-purposeful eating domain behaviors and overweight/obese BMI status.	Low interoception → ↓ self-regulation & ↑ non-purposeful eating → higher BMI.

Practical Takeaways for Researchers

Align tone and style with expectations of funding agencies, institutional review boards, and discipline-specific journals.

Section 4: Study Design Taxonomy & Evidence Synthesis 🔬

This section provides an extensive reference guide to quantitative study designs, epidemiologic measures, bias mitigation, and systematic review processes from a 101-page presentation (source).

4.1 Strength of Study Designs - Complete Taxonomy

Action Implementation Steps:

Action	How to Implement
Define a single, clear research question	Write it as a concise interrogative sentence; test it against the four planning questions.
Formulate specific aims/hypotheses	Ensure each aim directly answers the central question and is measurable.
Develop or adopt a conceptual framework	Diagram the presumed relationships (e.g., interoception → self-regulation → eating → BMI).
Assess feasibility	Draft a timeline, budget, and recruitment plan; verify staff expertise and institutional support.
Conduct an annotated bibliography	Summarize each source's methodology, findings, and relevance to your research question.
Choose the appropriate purpose-statement category	Align it with your aims (e.g., "Cause and Effect" for hypothesis-driven work).
Maintain scholarly voice	Use passive/active voice judiciously, avoid colloquialisms, and cite rigorously.

Study Design Overview - Typical Goals and Strengths:

Design	Typical Goal	Main Strength	Typical Data Structure
Case Report / Case Series	Describe a single patient or small group.	Provides detailed clinical insight; generates hypotheses.	No comparison group.
Single-Subject Design	Examine change within an individual over time.	Shows process of change; highly controlled.	Repeated measures on one participant.
Cross-Sectional Study	Estimate prevalence (snapshot).	Efficient for prevalence & correlational data.	One-time questionnaire/exam.
Repeated Cross-Sectional	Track prevalence over time using different samples.	Allows trend analysis.	Multiple independent cross-sections.

4.2 Key Epidemiologic Measures

Measures Overview:

Measure	Definition	Formula
Case Fatality Rate (CFR)	Proportion of identified cases that die.	CFR = (Deaths ÷ Cases) × 100%
Mortality Rate	Deaths in defined population over time.	Mortality = (Deaths ÷ Population) × 100,000
Proportionate Mortality Rate	Share of deaths from specific cause.	PMR = (Deaths from cause ÷ Total deaths) × 100%
Prevalence	Existing cases at point/period.	Prevalence = (Existing cases ÷ Population) × 100%
Incidence Rate	New cases per person-time at risk.	Incidence = (New cases ÷ Person-time at risk).

Planning Prompt:

Why It Matters: Emphasizes using EDP or PICOT structures to articulate the research question succinctly, applying the FINER criteria (Feasible, Interesting, Novel, Ethical, Relevant) as a quick quality filter.

Sourcing & Appraising Evidence

Internal validity: How well the study was designed & executed.
External validity: Applicability of findings to other groups.

Choosing the Right Design

Bias safeguards: Precise case definitions, blinding, randomization, and appropriate control groups reduce misclassification, recall, Hawthorne, and selection biases.

Measuring Associations & Effects

Odds Ratio (OR): Used primarily in case-control studies.
Risk Ratio (RR): Preferred for cohort designs.
Standardized Mean Difference (d): Effect size for continuous outcomes in meta-analyses.

Important Design Aspects:

One clear research question prevents scope creep and keeps the study focused.
Specific aims/hypotheses translate the question into observable, testable statements.
Conceptual/theoretical framework maps expected relationships (e.g., exposure → mediator → outcome) and guides analysis.
Feasibility checks ensure resources, timeline, and expertise match the scope.

Source Type & Appraisal Focus

Source Type	Typical Use	Appraisal Focus
Informal (agency fact-sheets)	Background context	Not peer-reviewed; verify authority.
Statistical reports	Population-level metrics	Check methodology & recency.
Research abstracts	Rapid scan for relevance	Assess clarity of objectives & methods.
Full-text articles	Core evidence	Evaluate internal & external validity, originality.

Summary of Study Design Goals

Design	Core Goal	Main Strength	Typical Data Shape
Case report/series	Generate hypotheses	Rich clinical detail	No comparison group.
Cross-sectional	Estimate prevalence	Efficient snapshot	One-time survey/exam.
Case-control	Study rare outcomes	Efficient for low-incidence disease	Retrospective exposure data.
Cohort (prospective)	Observe incidence & temporal sequence	Direct risk estimation	Longitudinal follow-up.
RCT (Randomized Controlled Trial)	Test intervention efficacy	Highest internal validity	Randomized groups, outcome measures.
Ecological	Policy-level inference	Uses aggregate data	Group-level exposures & outcomes.
Systematic review/meta-analysis	Synthesize existing evidence	Provides pooled effect sizes	Multiple studies pooled.

Diagnostic Test Metrics

(sensitivity, specificity, PPV, NPV): Guide test selection and interpretation.

Systematic Review Workflow

PICO-driven: Define a narrow question (Population, Intervention, Comparison, Outcome).
Craft reproducible search strings: Using MeSH terms and Boolean operators.
Screen titles/abstracts: Followed by full texts for eligibility.
Extract study characteristics and outcomes: Assess heterogeneity (Cochran’s Q, I²).
Choose pooling model: Fixed-effect for homogenous studies, random-effects when variability exists.
Visualize results: Use forest plots; check for publication bias via funnel plots.

Writing with Scholarly Voice

Maintain formal, objective language; avoid colloquialisms.
Cite peer-reviewed sources throughout the literature review and rationale.
Align tone with expectations of funding bodies, IRBs, and discipline-specific journals.

Integrating Example: Interoception & BMI

Study Goal: Link interoceptive sensibility → self-regulation → eating behavior → BMI.
Aims become testable hypotheses within a mediational framework (interoception → self-regulation → eating → BMI).
Design choice: Longitudinal cohort (exposure at age 15, mediators at 16, outcome at 19) ensures temporal ordering and permits mediation analysis.

Key Takeaways

Start with a single, well-crafted question and let it shape every methodological decision.
Match design to purpose (prevalence → cross-sectional; causality → cohort/RCT; synthesis → systematic review).
Apply rigorous appraisal (internal/external validity, bias checks) to all evidence sources.
Use frameworks (conceptual, theoretical, FINER) to keep the project coherent and feasible.
Report with scholarly voice and transparent methodology to maximize credibility and impact.