So sánh phương pháp

	Xây dựng Thang đo Likert	Floor and Ceiling Effect
Lĩnh vực	Trắc lượng tâm lý	Trắc lượng tâm lý
Họ	Process / pipeline	Process / pipeline
Năm ra đời	1932	2000
Người khởi xướng	Rensis Likert	Classical psychometrics
Loại	Summated rating scale methodology	Measurement validity assessment
Công trình gốc	Likert, R. (1932). A technique for the measurement of attitudes. Archives of Psychology, 22(140), 1-55.	McHorney, C. A. (2000). Ten recommendations for measuring health status. Health-Related Quality of Life Outcomes, 2(1), 1-5.
Tên gọi khác	Likert summated rating scale, Summated rating scale construction	Floor effect, Ceiling effect, Psychometric floor effect, Measurement floor
Liên quan	5	4
Tóm tắt	Likert scale construction is a systematic methodology for developing attitude measurement instruments using summated rating scales. Introduced by Rensis Likert in 1932, it enables researchers to quantify latent constructs such as attitudes, beliefs, and psychological states by aggregating responses across multiple items. The method remains foundational to quantitative social and health sciences research.	Floor and ceiling effects are psychometric phenomena in which a disproportionately large proportion of respondents achieve the lowest (floor) or highest (ceiling) possible score on a measurement scale. These effects compromise scale reliability and responsiveness, limiting the instrument's ability to distinguish among respondents and detect meaningful change over time. Systematic assessment of floor and ceiling effects is essential for evaluating the psychometric adequacy of health-related quality-of-life scales, functional status measures, and other patient-reported outcomes.