healthcare.antitrust (version 0.1.5)

impliedshare_calc: Implied Market Share Calculator

Description

Calculate implied market shares based on diversion ratios.

Usage

impliedshare_calc(
  M,
  div_from,
  quantities,
  focal,
  div_to,
  reference_goods,
  returnM = FALSE
)

Value

A list with two components. The first component, s_implied, is a vector of implied market shares for each good in the market. The second object, weights, is a vector of each good's corresponding membership weight in the market.

Arguments

M

Market size.

div_from

Vector of diversions from the focal good to other goods in the market, with each element between 0 and 1.

quantities

Vector of quantities or revenues for each good in the market.

focal

Scalar indicating the index of the focal good.

div_to

Vector of diversions to the focal good from other goods in the market, with each element between 0 and 1.

reference_goods

Vector indicating non-focal good(s) with diversion to focal good known, used to determine the market size.

returnM

logical; default to FALSE, in which case function returns implied shares for each good in the market and corresponding membership weight for each good. If TRUE, function can be used to find value of M which best matches observed diversions to focal good.

Details

This function calculates implied market shares based on given diversion ratios.

For more details see the example vignette by typing: vignette("semipar_example", package = "healthcare.antitrust")

Examples

q_1 <- 40
q_2 <- 20
div_1_2 <- .3333
div_2_1 <- .50

find_M <- optimize(f = impliedshare_calc, lower = 50, upper = 250,
   div_from=c(0,div_1_2), quantities=c(q_1,q_2), focal=1,
   div_to=c(0,div_2_1), reference_goods = c(2), returnM = TRUE)

find_M
M_implied <- find_M$minimum


impliedshare_calc(M=M_implied,div_from=c(0,div_1_2),
   quantities=c(q_1,q_2),
   focal=1, div_to=c(0,div_2_1),reference_goods = c(2))