MatchinMarkets package

Documentation for the package https://cran.r-project.org/web/packages/matchingMarkets/matchingMarkets.pdf

On page 32, how is c1:s1 computed in the data on running the following example code:

3. Correction for sorting bias when match valuations V are unobserved ## 3-a. Run Gibbs sampler (when SEL is given)

fit2 <- stabit2(OUT = xdata$OUT, 
SEL = xdata$SEL, 
outcome = y ~ c1:s1, 
selection = ~-1 + c1:s1, niter=1000 )