Outcome-Driven Regression: Choosing the Right Model Based on Y in Clinical Research
Why start with Y ? Because the distribution and scale of the outcome (not the exposure) dictate: The likelihood function behind the...
How to Order LPRC Transfusion (Also CPM) for Symptomatic Anemia in IPD Settings
In non-emergency IPD (inpatient department) settings, transfusion of Leukocyte-Poor Red Cells (LPRC) is commonly done for symptomatic...
What is Marginalisation in Clinical Statistics?
Marginalisation refers to the process of transforming effect estimates derived from specific subgroups (i.e., conditional on covariates...
Collapsibility Explained with Clinical Logic: When Crude Equals Adjusted (and When It Doesn’t)
🧩 Collapsible = “Crude ≈ Adjusted” If you don’t adjust for age/sex and then do adjust , the result doesn’t change much. 💊 Example:...
What Is Collapsibility in Clinical Statistics?
Collapsibility is a property of effect measures that determines whether the measure changes when you (statistically) adjust or don’t...
Choosing the Right Regression Model: A Visual Guide for Outcome Types in Clinical Research
In clinical epidemiology and biostatistics, choosing the correct regression model hinges on the characteristics of the outcome variable...
Logistic Regression สำหรับข้อมูล Binary: ทำไมใช้ได้ แม้ Y มีแค่ 0 กับ 1
🔍 ปัญหาเริ่มต้น: “ถ้า Y มีแค่ 1 หรือ 0 แล้วจะวิเคราะห์ยังไง?” หลายคนสงสัยว่า ถ้า Y มีแค่ “มีโรค” (1) หรือ “ไม่มีโรค” (0)...
Four Essential Assumptions for Causal Inference: Exchangeability, Positivity, No Interference, Consistency, and SUTVA
1. Exchangeability (Ignorability) 🔎 What it means: After adjusting for the observed covariates X, the treated and untreated groups are...
Causal Inference in Observational Research: Strategies, Assumptions, and Stata Tools
1 Why Observational Data Are Harder Than RCTs RCT privilege What you lose in an observational study Investigator controls treatment →...
Causal Inference in RCTs: ITT, CACE, and Estimands in Practice
Causal Inference inside an RCT – STATA-First Edition 0 Glossary of Key Abbreviations Short-form Stands for Meaning in this document R...
Why Causality Matters: A Primer for Medical Research (Causal Inference)
1 Why Causality Matters Correlation → two variables move together. Causation → changing exposure X would change outcome Y for the...
Parametric Survival Analysis: Modelling Time-to-Event Data When the Hazard Has a Predictable Shape
Introduction Time-to-event studies frequently rely on Cox proportional-hazards regression because it requires no a priori specification...
Incidence Rate, Hazard, and Cox Regression: Distinctions in Time-to-Event Research
Table of Different slices of risk in time-to-event research : Concept Core question answered Typical notation (plain text) Where is it...
Cox Proportional Hazards Regression and Related Survival-Analysis Concepts
Introduction Clinical and public-health investigations often focus not only on whether an outcome occurs but also on when it occurs....
Survival Analysis in Stata: stset and sts – Kaplan-Meier
1. Declaring Survival Data with stset Purpose: The stset command in Stata designates your dataset as survival (time-to-event) data. This...
Time-to-Event (Survival) Analysis: Essentials for Clinical Researchers
Introduction Time-to-event analysis, commonly referred to as survival analysis, is a cornerstone methodology in clinical research and...
Merge vs Append in Stata: The Clinical Data Join Guide
Stata’s merge and append are among the first data management tools you’ll use in real clinical research. But when should you use each?...
Systemic Lupus Erythematosus (SLE) Guide: ANA-10 Rule, EULAR/ACR Criteria, and Treat-to-Target Plan
1. Diagnosis & Classification (2019 EULAR/ACR) Step How to Apply at the Bedside Key Numbers & Rules Entry criterion Confirm ANA by...
Inflammatory Myopathies (IIM): Polymyositis and Dermatomyositis “WEAK MUSCLE” Diagnosis, Staging, and Step-Care Treatment Plan By 2017 EULAR/ACR probability score
1 Pathophysiology & Clinical Presentation Key point Polymyositis (PM) Dermatomyositis (DM) Immune driver CD8⁺ T-cell–mediated myofibre...