เปรียบเทียบวิธี

	การศึกษาเฟส 4	การศึกษาทางระบาดวิทยาภาคตัดขวาง
สาขาวิชา	ระบาดวิทยา	ระบาดวิทยา
ตระกูล	Process / pipeline	Process / pipeline
ปีกำเนิด	Formalised 1970s–1990s (ICH E3 guideline 1994)	1960s (formal codification); widely practiced since mid-20th century
ผู้ริเริ่ม	Regulatory agencies and pharmaceutical industry (ICH, FDA, EMA frameworks)	Classical epidemiology tradition; systematized by Brian MacMahon and Thomas Pugh (1960s)
ประเภท	Post-marketing observational or interventional study	Observational, descriptive/analytic epidemiological design
แหล่งต้นตำรับ	International Conference on Harmonisation (ICH). (1994). ICH Harmonised Tripartite Guideline: Structure and Content of Clinical Study Reports E3. ICH Secretariat.	Kelsey, J. L., Whittemore, A. S., Evans, A. S., & Thompson, W. D. (1996). Methods in Observational Epidemiology (2nd ed.). Oxford University Press. ISBN: 978-0195080407
ชื่อเรียกอื่น	post-marketing surveillance study, post-approval study, Phase 4 study, PMS study	prevalence study, cross-sectional survey, transversal study, cross-sectional design
ที่เกี่ยวข้อง	5	6
สรุป	A Phase IV study is a post-marketing surveillance study conducted after a drug, device, or intervention has received regulatory approval. Its primary purpose is to monitor long-term safety, detect rare adverse events, assess effectiveness in routine clinical practice, and explore new indications or populations not adequately represented in earlier trials. Phase IV evidence accumulates continuously throughout a product's commercial life.	A cross-sectional epidemiological study measures the exposure(s) and outcome(s) of interest simultaneously in a defined population at a single point in time (or over a short period). Because there is no follow-up, it is the most efficient observational design for estimating disease prevalence and for generating hypotheses about associations between risk factors and health outcomes.