QCA (version 3.3)

modelFit: Theory evaluation

Description

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().

Usage

modelFit(model, theory)

Arguments

model

A minimization object of class "qca".

theory

Character, a SOP expression.

Value

A list containing objects of class "pof" with the parameters of fit. For a single theoretical expression and a single model, the object is a simple "pof" object.

Details

Following Ragin's (1987) original work, theory evaluation amounts to intersecting a theoretical expectation with a model resulting from a minimization process.

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.

References

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). Cambridge: Cambridge University Press.

See Also

intersection, negate, pof

Examples

# NOT RUN {
# Lipset fuzzy version data
data(LF)
ttLF <- truthTable(LF, outcome = "SURV", incl.cut = 0.8)


# parsimonious solution
pLF <- minimize(ttLF, include = "?")

modelFit(model = pLF, theory = "DEV*STB")


# hypothetical exploration of intermediate solutions
iLF <- minimize(ttLF, include = "?", dir.exp = "1,0,0,0,0")

modelFit(iLF, "DEV*STB")

# }