PhD Resources
Browse articles by category and topic.
-
Construct, Internal, and External Validity in Research Design Explained (2026)
A research-grade guide to construct, internal, external, and statistical conclusion validity — covering the Cook & Campbell typology, all major…
-
PhD Student Mental Health Statistics 2026: Anxiety, Depression and Burnout Prevalence Data
Data on PhD student mental health in 2026: depression (24%), anxiety (17%), burnout (39%). Sourced from Nature surveys, meta-analyses, and…
-
Directed Acyclic Graphs (DAGs) for Causal Inference 2026: A Researcher’s Guide
A reference-grade methods guide to directed acyclic graphs (DAGs) for causal inference: nodes, edges, confounders, colliders, mediators, the backdoor criterion,…