Function to enable theory evaluation, as introduced by Ragin (1987, p.118)
and extended Schneider & Wageman (2012, p.295), by producing parameters of fit
for all possible intersections between a given theoretical statement (a SOP
expresison) and the solutions found by function
minimize().
modelFit(model, theory)
model |
A minimization object of class "QCA_min". |
|||
theory |
Character, a SOP expression. |
There are in fact four intersections: presence - presence, presence - absence,
absence - presence and absence - absence, where by "absence" is actually
meant a negation of an expression using the function
negate().
When multiple models exist, all of them are automatically detected, negated and intersection with the theory. Intersections and parameters of fit are going to be produced using a single theoretical expression.
"QCA_pof" with the parameters of fit. For a
single theoretical expression and a single model, the object is a simple
"QCA_pof" object.
Ragin, C.C. (1987) The Comparative Method: Moving beyond Qualitative and Quantitative Strategies. Berkeley: University of California Press.
Schneider, C.Q.; Wagemann, C. (2012) Set-Theoretic Methods for the Social Sciences: A Guide to Qualitative Comparative Analysis (QCA). Berkeley: University of California Press.
# Lipset fuzzy version data ttLF <- truthTable(LF, outcome = "SURV", incl.cut = 0.8) # parsimonious solution pLF <- minimize(ttLF, include = "?") modelFit(model = pLF, theory = "DEV*STB")model: DEV*~IND + URB*STB theory: DEV*STB model*theory: DEV*URB*STB + DEV*~IND*STB model*~theory: ~DEV*URB*STB + DEV*~IND*~STB ~model*theory: DEV*~URB*IND*STB ~model*~theory: ~DEV*~URB + ~DEV*~STB + IND*~STB inclS PRI covS -------------------------------------- 1 DEV*~IND 0.815 0.721 0.284 2 URB*STB 0.874 0.845 0.520 3 model 0.850 0.819 0.714 4 theory 0.869 0.848 0.824 5 model*theory 0.866 0.839 0.660 6 model*~theory 0.688 0.422 0.191 7 ~model*theory 0.709 0.634 0.237 8 ~model*~theory 0.234 0.057 0.255 --------------------------------------# hypothetical exploration of intermediate solutions iLF <- minimize(ttLF, include = "?", dir.exp = "1,0,0,0,0") modelFit(iLF, "DEV*STB")M-C1P1 model: DEV*URB*STB + DEV*~URB*~IND theory: DEV*STB model*theory: DEV*URB*STB + DEV*~URB*~IND*STB model*~theory: DEV*~URB*~IND*~STB ~model*theory: DEV*~URB*IND*STB ~model*~theory: ~DEV + URB*~STB + ~URB*IND*~STB inclS PRI covS -------------------------------------- 1 DEV*URB*STB 0.901 0.879 0.468 2 DEV*~URB*~IND 0.806 0.719 0.268 3 model 0.866 0.839 0.662 4 theory 0.869 0.848 0.824 5 model*theory 0.866 0.839 0.660 6 model*~theory 0.671 0.311 0.122 7 ~model*theory 0.709 0.634 0.237 8 ~model*~theory 0.254 0.091 0.295 --------------------------------------