The Core of Clinical Research Design in 3 Moves: Object, Method, Analysis

1️⃣ Object Design: What’s the Clinical Problem?

Use the DEPTh Model to define your study’s core question:

DEPTh Type	Clinical Aim	Example Question
Diagnosis	Identify disease	“Can symptoms predict TB?”
Etiognosis	Find a cause	“Does drug X cause liver injury?”
Prognosis	Predict future outcomes	“What predicts ICU stay after surgery?”
Therapeutic	Assess treatment effect	“Does intervention A reduce readmission?”
Methodologic	Improve measurement tools	“Is test B reproducible in clinical use?”

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2️⃣ Method Design: How Will You Study It?

Break the object into method components:

Element	What It Does
Study Domain	Clinical population & setting
Study Base (3x3x3)	Who, where, and when the sample is drawn
Determinants (X)	Risk factors, exposures, or treatments
Endpoints (Y)	What happens (outcome, diagnosis, recovery, etc)
Clinical Parameters	Time, rates, odds, mean change
Occurrence Equation	Links everything in one analytic model

✳️ Occurrence Equation

Model your outcome as a function of causes or predictors:

Where:

• Y = Outcome (event, diagnosis, measurement)

• Xs = Main exposures, treatments, or predictors

• Confounders = Other variables that distort true relationship

• Bias = Selection, measurement, or analysis artifacts

• Random error = Chance variation
  

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3️⃣ Analysis Design: How Will You Analyze It?

Match the analytic method to the DEPTh type:

Logic Type	Used For	Goal
Describe	All studies	Summarize population/data
Explain	Etiognostic, Therapeutic	Identify causal effects
Explore	Early phase, hypothesis-gen	Discover new relationships
Predict	Diagnostic, Prognostic	Forecast who gets what/when

🛠 Common tools:

• Describe: Means, medians, proportions

• Explain: Logistic/Cox/Linear regression

• Predict: Risk scores, ML models, ROC/AUC
  

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✅ Quick Recap

• DEPTh = Your research compass 🧭

• Occurrence Equation = Your modeling skeleton 💀

• Design Triad:

  • Object = What are you solving?

  • Method = How will you study it?

  • Analysis = How will you prove or predict?

    
    

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🧪 Practice Prompt

Try filling in this template for your next idea:

• DEPTh Type:

• Clinical Question:

• Y =

• f(Xs | Confounders)

• Analysis Goal: Describe / Explain / Explore / Predict