Ceiling effect

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
Range constriction
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.

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