| dropRollCall {pscl} | R Documentation |
Drop user-specified elements of rollcall object, returning a roll call object.
dropRollCall(object, dropList)
object |
an object of class rollcall |
dropList |
a list (or alist) with
some (or all) of the following components:
codesobject$codes,
indicating the set of entries in object$votes to be set to
NA. If numeric, then codes indicates the entries in
object$votes that will be set to NA.lopobject. Roll calls with lop
or fewer legislators voting in the minority are dropped.legisMinobject. Legislators with
legisMin or fewer votes are dropped.dropLegisexpression that evaluates to
mode logical, vector of length equal to the number of
legislators represented in object. The expression is evaluated
in the legis.data component of the rollcall object.
Legislators for whom the expression evaluates to TRUE are
dropped.dropVotesexpression that evaluates to
mode logical, vector of length equal to the number of
rollcalls represented in object. The expression is evaluated
in the votes.data component of the rollcall object.
Rollcalls for which the expression evaluates to TRUE are
dropped. |
It is often desirable to restrict the analysis of roll call
data in various ways. For one thing, unanimous votes provide no
information discriminating among legislators: hence, a useful
default for summary and analysis is dropList=list(lop=0).
See the examples for other possibilities, limited only by the
information supplied in legis.data and votes.data.
An object of class rollcall with components modified by
the subsetting indicated in the dropList.
With the exception of codes, each component of
dropList generates a vector of mode logical,
either with respect to legislators or votes. These logical
vectors are then combined element-wise, such that if any one of
the subseting restrictions is TRUE for a particular
legislator or vote, then that legislator or vote is dropped. Some
summaries are reported to the console along the way.
When dropList uses the dropLegis or dropVotes
components then dropList should be constructed as an
alist command; this ensures that the
dropLegis and dropVotes components of
dropList are objects of mode expression, and
evaluated to mode logical in the
legis.data and vote.data environments by
the function, if possible (rather than being evaluated immediately in
the environment calling dropRollCall or constructing
dropList). See the examples. This is not entirely
satisfactory, and behavior more like the subset argument in
function lm would be preferable.
Simon Jackman jackman@stanford.edu
dropUnanimous, summary.rollcall,
ideal, alist.
data(s109)
s109.working <- dropRollCall(s109,
dropList=list(lop=0))
s109.working <- dropRollCall(s109,
dropList=list(lop=0,
code="notInLegis"))
s109.working <- dropRollCall(s109,
dropList=list(lop=3,
code="notInLegis"))
## note use of alist, since dropLegis is an expression
dropList <- alist(lop=3,
dropLegis=party!="D",
code="notInLegis")
s109.working <- dropRollCall(s109,dropList=dropList)