Questionnaire Dwelling Unit-Level and Person Pair-Level Sampling ...

C.2 Glossary of Terms Used in the Description of the Variables in the Final
Model
Factor effect. The factor effect represents the effects of levels considered for one factor,
two factors, and higher order factors.
Reference/reference set. Factor effects composed of reference levels are not explicitly
listed in the set of model variables. However, these effects manifest themselves either separately
or in combination with other factors depending on the presence of other factors in the model.
All levels present. All effects and all levels of the factor under consideration are in the
model.
Coll. (levels). Collapse these factor effects together. Factor effects that have been
collapsed with others manifest themselves jointly in the model.
Drop all levels. All factor effects are completely removed from the model for all levels
and any combinations involving this factor.
Drop level(s). Collapse these factor effects into the reference set. The factor effects
comprising the dropped levels are manifested jointly with either some or all of the factor effects
in the reference set.
Drop level(s); sing. During the modeling process the factor effects listed are removed
from the model due to singularity.
Drop level(s); zero cnts. During the modeling process the factor effects listed are
removed from the model due to zero sample.
Hier. One or more of the effects in a higher order interaction is collapsed or dropped in
an interaction at a lower order, either eliminating or combining factors of higher order
interactions with that effect.
Do the same for (effects). Repeat the previous step for all effect levels listed.
Drop or Collapse using*. The asterisk is used as a wild card character to indicate all
levels of the factor for that effect.
Note: The above glossary is given as a list of general terms. Certain other specific terms are
sometimes used within a particular section.
C-7