Floor Effects Research

Psychology definition of floor effect.

Floor effects research.

Let s talk about floor and ceiling effects for a minute. Limited variability in the data gathered on one variable may reduce the power of statistics on correlations between that variable and another variable. In layperson terms your questions are too hard for the group you are testing. I am interested to find the way i can statistically assess them.

The inability of a test to measure or discriminate below a certain point usually because its items are too difficult. In research a floor effect aka basement effect is when measurements of the dependent variable the variable exposed to the independent variable and then measured result in very low scores on the measurement scale. For example the distribution of scores on an ability test will be skewed by a floor effect if the test is much too difficult for many of the respondents and many of them obtain zero scores. Floor effects are occasionally encountered in psychological testing when a test designed to estimate some psychological trait has a minimum standard score that may not distinguish some test takers who differ in their responses on the test item content.

The term ceiling effect is a measurement limitation that occurs when the highest possible score or close to the highest score on a test or measurement instrument is reached thereby decreasing the likelihood that the testing instrument has accurately measured the intended domain. A floor effect is when most of your subjects score near the bottom. There is very little variance because the floor of your test is too high. A ceiling effect can occur with questionnaires standardized tests or other measurements used in research studies.

Description in some fields biology physiology etc the ceiling effect refers to the point at which an independent variable no longer has an effect on a dependent variable when a kind of saturation has been reached e g the phenomenon in which a drug reaches its maximum effect so that increasing the. Ceiling effects and floor effects both limit the range of data reported by the instrument reducing variability in the gathered data. A floor effect occurs when a measure possesses a distinct lower limit for potential responses and a large concentration of participants score at or near this limit the opposite of a ceiling effect. In statistics and measurement theory an artificial lower limit on the value that a variable can attain causing the distribution of scores to be skewed.

The opposite is the floor effect.