Unanchored items with extreme (zero, minimum possible or perfect, maximum possible) scores provide no information for estimating person measures, but they are reported and included in summary statistics. To remove them:

 

IDROPEXTREME = No ; do not drop extreme items (standard)

 

IDROPEXTREME = Yes or All ; drop items with zero (minimum possible) and perfect (maximum possible) scores

 

IDROPEXTREME = Zero or Low or Bottom or Minimum ; drop items with zero or minimum-possible scores

 

IDROPEXTREME = Perfect or High or Top or Maximum ; drop items with perfect or maximum-possible scores

 

Example: The instrument contains items asking about very rare conditions (scored "0" - not observed). These are skewing the survey summary statistics:

 IDROPEXTREME = Minimum ; items about conditions never observed in the sample are dropped.