| dropRollCall {pscl} | R Documentation |
Drop user-specified elements of rollcall object, returning a roll call object.
dropRollCall(object, dropList,debug=FALSE)
object |
an object of class rollcall |
dropList |
a list (or alist) with
some (or all) of the following components:
object$codes,
indicating the set of entries in object$votes to be set to
NA. If numeric, then codes indicates the entries in
object$votes that will be set to NA.object. Roll calls with lop
or fewer legislators voting in the minority are dropped.object. Legislators with
legisMin or fewer votes are dropped.expression 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.expression 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. |
debug |
logical, set to TRUE to see messages
printed to the console as inspection and subsetting of the
rollcall object takes place |
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,
summary and analysis should almost always use 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/added 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 if debug=TRUE.
dropRollCall adds a component
named dropInfo to the rollcall object it returns. This
component is itself a list containing named components
logical, with each
element TRUE if the legislator is retained in the returned
rollcall object.logical, with each element
TRUE if the corresponding is retained in the returned
rollcall object.dropList supplied as input to
dropRollCall.
If the input rollcall object is itself the product of a call to
dropRollCall, the dropInfo component on output is a list
with named components
dropInfo component of the input
rollcall object.dropInfo list created by the current call to
dropRollCall.
Functions like summary.rollcall try to handle this information
sensibly.
When dropList uses the dropLegis or dropVotes
components then dropList should be constructed via the
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))
summary(s109.working)
s109.working <- dropRollCall(s109,
dropList=list(lop=0,
code="notInLegis"))
summary(s109.working)
s109.working <- dropRollCall(s109,
dropList=list(lop=3,
code="notInLegis"))
summary(s109.working)
## note use of alist, since dropLegis is an expression
dropList <- alist(lop=3,
dropLegis=party!="D",
code="notInLegis")
s109.working <- dropRollCall(s109,dropList=dropList,debug=TRUE)
summary(s109.working)
s109.working <- dropRollCall(s109.working,dropList=list(legisMin=25))
summary(s109.working)
## Not run:
## read 102nd House from Poole web site
h102 <- readKH("ftp://voteview.ucsd.edu/dtaord/hou102kh.ord")
## drop President from roll call matrix
h102 <- dropRollCall(h102,
dropList=alist(dropLegis=state=="USA"))
summary(h102)
## End(Not run)