View source: R/define_statistic_wrapper.R
define_statistic_wrapper | R Documentation |
define_statistic_wrapper
defines
statistic wrappers to be used together with
variance estimation wrappers
.
A statistic wrapper produces both the point estimator and the
linearized variable associated with a given statistic to estimate
variance on (Deville, 1999). define_statistic_wrapper
is intended
for advanced use only, standard statistic wrappers are included
in the gustave package (see standard statistic wrappers
)
define_statistic_wrapper( statistic_function, arg_type, arg_not_affected_by_domain = NULL, display_function = standard_display )
statistic_function |
An R function specific to the statistic to calculate. It should produce at least the point estimator and the linearized variable associated with the statistic (see Details). |
arg_type |
A named list with three character vectors describing
the type of each argument of |
arg_not_affected_by_domain |
A character vector indicating the arguments which should not be affected by domain-splitting. Such parameters may appear in some complex linearization formula, for instance when the At-Risk of Poverty Rate (ARPR) is estimated by region but with a poverty line calculated at the national level. |
display_function |
An R function which produces, for each variance
estimation, the data.frame to be displayed by the variance estimation
wrapper. The default display function ( |
When the statistic to estimate is not a total, the application of analytical variance estimation formulae developed for the estimator of a total is not straightforward (Deville, 1999). An asymptotically unbiased variance estimator can nonetheless be obtained if the estimation of variance is performed on a variable obtained from the original data through a linearization step.
define_statistic_wrapper
is the function used to create, for a
given statistic, an easy-to-use function which calculates both the point
estimator and the linearized variable associated with the statistic. These
operations are implemented by the statistic_function
, which can have
any needed input (for example num
and denom
for a ratio
estimator) and should output a list with at least two named elements:
point
: the point estimator of the statistic
lin
: the linearized variable to be passed on to the variance
estimation formula. If several variables are to be associated with
the statistics, lin
can be a list itself.
All other named elements in the output of define_statistic_wrapper
are
treated as metadata (that may be used later on by display_function
).
arg_type
is a named list of three elements that describes the nature
of the argument of statistic_function
:
data
: data argument(s), numerical vector(s) to be used
to calculate the point estimate and the linearized variable associated
with the statistic
weight
: weight argument, numerical vector to be used
as row weights
param
: parameters, non-data arguments to be used to
control some aspect of the computation
Statistic wrappers are quite flexible tools to apply a variance function to an estimator requiring a linearization step (e.g. all estimators except the estimator of a total) with virtually no additional complexity for the end-user.
standard statistic wrappers
are included within the gustave package and automatically added
to the variance estimation wrappers. New statistic wrappers can be defined
using the define_statistic_wrapper
and then explicitly added to the
variance estimation wrappers using the objects_to_include
argument.
Note: To some extent, statistic wrappers can be seen as ggplot2
geom_
and stat_
functions: they help the end-user in writing
down what he or she wants without having to go too deep into the details
of the corresponding layers.
A function to be used within a variance estimation wrapper to estimate
a specific statistic (see examples). Its formals are the ones of
statistic_function
with the addition of by
and where
(for domain estimation, set to NULL
by default).
Martin Chevalier
Deville J.-C. (1999), "Variance estimation for complex statistics and estimators: linearization and residual techniques", Survey Methodology, 25:193–203
standard statistic wrappers
, define_variance_wrapper
### Example from the Information and communication technologies (ICT) survey # Let's define a variance wrapper asfor the ICT survey # as in the examples of the qvar function: precision_ict <- qvar( data = ict_sample, dissemination_dummy = "dissemination", dissemination_weight = "w_calib", id = "firm_id", scope_dummy = "scope", sampling_weight = "w_sample", strata = "strata", nrc_weight = "w_nrc", response_dummy = "resp", hrg = "hrg", calibration_weight = "w_calib", calibration_var = c(paste0("N_", 58:63), paste0("turnover_", 58:63)), define = TRUE ) precision_ict(ict_survey, mean(speed_quanti)) # Let's now redefine the mean statistic wrapper mean2 <- define_statistic_wrapper( statistic_function = function(y, weight){ point <- sum(y * weight) / sum(weight) lin <- (y - point) / sum(weight) list(point = point, lin = lin, metadata = list(n = length(y))) }, arg_type = list(data = "y", weight = "weight") ) # mean2 can now be used inside precision_ict (and yields # the same results as the mean statistic wrapper) precision_ict(ict_survey, mean(speed_quanti), mean2(speed_quanti))
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