parse_formula

This function takes nonstandard formulas as inputs and returns regular formulas
as well as lists of weights to be used in <code>generate_constraints()</code>.

internal

Natural strata can be used in observational studies to balance
the distributions of many covariates across any number of treatment
groups and any number of comparisons. These strata have proportional
amounts of units within each stratum across the treatments, allowing
for simple interpretation and aggregation across strata. Within each
stratum, the units are chosen using randomized rounding of a linear
program that balances many covariates. For more details, see Brumberg et al. (2022) <doi:10.1111/rssa.12848> and Brumberg et al.(2023) <doi:10.1093/jrsssc/qlad010>.
To solve the linear program, the 'Gurobi' commercial optimization software
is recommended, but not required. The 'gurobi' R package can be installed by following the instructions at <https://docs.gurobi.com/projects/optimizer/en/current/reference/r/setup.html> after claiming your free academic license at <https://www.gurobi.com/academia/academic-program-and-licenses/>.

Katherine Brumberg

natstrat

Obtain Unweighted Natural Strata that Balance Many Covariates

parse_formula function

<dl><dt>balance_formula</dt>
<dd>a formula that may have multiple terms on the left hand side,
"." on the left hand side, and coefficients, making it not a standard formula.</dd>
<dt>default_rhs</dt>
<dd>the list of <code>balance_formulas</code> can also contain entries
that are just the character corresponding to a covariate to balance. If so,
the covariate will be balanced according to <code>default_rhs</code>.</dd>
<dt>data</dt>
<dd>a data frame containing the relevant covariates in the columns. The number
of rows should equal the length of <code>treated</code>.</dd></dl>

Arguments

Parse the nonstandard balance formulas — parse_formula

<dl>

<dt>balance_formula</dt>
<dd>a formula that may have multiple terms on the left hand side,
"." on the left hand side, and coefficients, making it not a standard formula.</dd>


<dt>default_rhs</dt>
<dd>the list of <code>balance_formulas</code> can also contain entries
that are just the character corresponding to a covariate to balance. If so,
the covariate will be balanced according to <code>default_rhs</code>.</dd>


<dt>data</dt>
<dd>a data frame containing the relevant covariates in the columns. The number
of rows should equal the length of <code>treated</code>.</dd>

</dl>

parse_formula: Parse the nonstandard balance formulas

Description

Usage

Value

Arguments