howard.xcl2: Howard-Newman-Tarp excess colocation (XCL) index
In REAT: Regional Economic Analysis Toolbox

Description Usage Arguments Details Value Author(s) References See Also Examples

Calculating the excess colocation (XCL) index by Howard, Newman and Tarp for a given number of industries

1	howard.xcl2(k, industry, region, print.results = TRUE)

`k`	a vector containing the IDs/names of firms k
`industry`	a vector containing the IDs/names of the industries i
`region`	a vector containing the IDs/names of the regions j
`print.results`	logical argument that indicates whether the calculated values are printed or not

The Howard-Newman-Tarp excess colocation index (XCL) is standardized (-1 ≤ CL ≤ 1). The rationale behind is that the CL index (see howard.cl) is compared to a counterfactual (random) location pattern which is constructed via bootstrapping. Processing time depends on the number of firms and the number of samples. This function takes a while even for a relatively small number of industries!

A matrix with I rows (one for each industry-industry combination) containing the XCL values

Thomas Wieland

Howard, E./Newman, C./Tarp, F. (2016): “Measuring industry coagglomeration and identifying the driving forces”. In: Journal of Economic Geography, 16, 5, p. 1055-1078.

howard.cl, howard.xcl2, ellison.c, ellison.c2

## Not run: 
# example data from Farhauer/Kroell (2014):
data (FK2014_EGC)

howard.xcl2 (FK2014_EGC$firm, FK2014_EGC$industry, 
FK2014_EGC$region)
# this may take a while!

## End(Not run)