Compară metode

	Scara Guttman	Efectul de "podea" și de "tavan"
Domeniu	Psihometrie	Psihometrie
Familie	Process / pipeline	Process / pipeline
Anul apariției	1944	2000
Autorul original	Louis Guttman	Classical psychometrics
Tip	Cumulative unidimensional scaling methodology	Measurement validity assessment
Sursa seminală	Guttman, L. (1944). A basis for scaling qualitative data. American Sociological Review, 9(2), 139-150.	McHorney, C. A. (2000). Ten recommendations for measuring health status. Health-Related Quality of Life Outcomes, 2(1), 1-5.
Denumiri alternative	Cumulative scale, Scalogram analysis, Guttman scaling, Unidimensional cumulative scale	Floor effect, Ceiling effect, Psychometric floor effect, Measurement floor
Înrudite	4	4
Rezumat	Guttman scaling is a methodology for constructing unidimensional scales with a cumulative property, developed by Louis Guttman in 1944. The method assumes that items form a perfect or near-perfect hierarchy: if a respondent endorses a harder item, they must endorse all easier items below it. This creates a reproducible scale structure useful for measuring constructs with ordinal properties such as difficulty, intensity, or severity.	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.