When resources can be ordered based on a property or
on some externally-defined numbering system, that
order can define draw priority. For example, trucks of
varying size can be sorted by their loading capacity,
where it may have been decided that larger ones will be
loaded first; an engineer may have numbered footings
to specify the order in which concrete is to be placed,
where those with lower numbers will be placed first.
Selection is thus based on comparing an individual
resource's "capacity" or "placement number" property
with that of others in the same queue. Other examples
are "easiest to install first" and "highest ratio of earnedto-
expended effort first" (Howell and Ballard 1996),