Provide function to access employment counts

[brandones]

Calculating employment multipliers requires access to per-industry employment averages. Right now stateior does not, as far as I know, provide any way to access that information, despite the fact that that information is used in producing the IO tables. Sectoral employment from elsewhere (e.g. QCEW) generally does not align with the BEA Summary IO 2012 Schema. I am able to get the necessary information using the following code, mostly cribbed from getStateEmploymentbyBEASummary:

readCSV <- function(filename, fill = FALSE) {
  df <- utils::read.table(filename, sep = ",", header = TRUE,
                          stringsAsFactors = FALSE, check.names = FALSE,
                          fill = fill, fileEncoding = "UTF-8-BOM")
  return(df)
}

loadBEAStateDatatoBEASummaryMapping <- function(dataname) {
  filename <- paste0("Crosswalk_State", dataname, "toBEASummaryIO2012Schema.csv")
  mapping <- readCSV(system.file("extdata", filename, package = "stateior"))
  return(mapping)
}

getStateEmploymentTable <- function(year) {
  BEAStateEmp <- loadStateIODataFile(paste0("State_Employment_", year))
  loadBEAStateDatatoBEASummaryMapping("Employment")
  EmptoBEAmapping <- loadBEAStateDatatoBEASummaryMapping("Employment")
  BEAStateEmp <- merge(BEAStateEmp[, c("GeoName", "LineCode", as.character(year))],
                        EmptoBEAmapping, by = "LineCode")
  BEAStateEmp <- stats::aggregate(BEAStateEmp[, as.character(year)],
                                  by = list(BEAStateEmp$BEA_2012_Summary_Code,
                                            BEAStateEmp$GeoName), sum)
  colnames(BEAStateEmp) <- c("BEA_2012_Summary_Code", "State", "Emp")
  return(BEAStateEmp)
}

getStateEmploymentTable(2019)

stateior should simply export a function like getStateEmploymentTable to make employment data accessible.

ASIDE: Why not do the same for the Leontief matrices?

[WesIngwersen]

We have this type of functionality in the model building package useeior. We're using useeior to build state-level two region environmentally-extended input-output models and calculate equivalents to multipliers, including for employment. The environmental extensions are totally optional. Here is an example model output for Colorado with link that include the description of the code that was used. Due to resource constraints and a small team maintaining all of our Tools for Industrial Ecology Modeling of which this package is a part of, we don't plan to add that kind of equivalent functionality into stateior at this time. thanks for your interest!

[brandones]

I see. That looks a lot more complicated to use. Would you consider PRs to add this kind of functionality to stateior, if I were to open them? I think it would be pretty simple; mostly just exposing to the user what is already available internally.

[WesIngwersen]

I see. That looks a lot more complicated to use. Would you consider PRs to add this kind of functionality to stateior, if I were to open them? I think it would be pretty simple; mostly just exposing to the user what is already available internally.

Sure, exporting more functions or wrapping them with some simple functionality is fine. Thanks for your offer, i look forward to reviewing the PR.

[brandones]

Opened #44