So sánh phương pháp

	Floor and Ceiling Effect	Xây dựng Thang đo Likert
Lĩnh vực	Trắc lượng tâm lý	Trắc lượng tâm lý
Họ	Process / pipeline	Process / pipeline
Năm ra đời	2000	1932
Người khởi xướng	Classical psychometrics	Rensis Likert
Loại	Measurement validity assessment	Summated rating scale methodology
Công trình gốc	McHorney, C. A. (2000). Ten recommendations for measuring health status. Health-Related Quality of Life Outcomes, 2(1), 1-5.	Likert, R. (1932). A technique for the measurement of attitudes. Archives of Psychology, 22(140), 1-55.
Tên gọi khác	Floor effect, Ceiling effect, Psychometric floor effect, Measurement floor	Likert summated rating scale, Summated rating scale construction
Liên quan	4	5
Tóm tắt	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.	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.