| In OM this refers to most people choosing the maximum possible score on an item or a scale. This leaves no scope to record differences above this ceiling. A floor effect is the opposite: most or all people scoring on the lowest possible score. Both limit the Variance of scores. A ceiling effect can make an item, or, much more seriously, a whole OM score insensitive to differences and change above the “ceiling” so an item like “I have felt unhappy” may be fine to detect differences in general well-being but won’t distinguish between those with mild low mood and those in a deeply despairing state. |
Detail #
Bit more about diagnosing it, impact and about IRT?
Try also … #
Floor effect
Variance
Range
Range constriction
Bias
Validity & invalidity
Item Response Theory
Chapters #
Nothing here yet!
Further reading #
Nothing here yet!
Online tools #
Possible simulation and perhaps diagnostics for ceiling and floor effects.
