Description Usage Arguments Details Value Contributors (alphabetical) Author(s) References See Also Examples
This evaluation function computes the degree of ambiguity across variations of a reference design. It has initially been programmed for Baumgartner and Thiem (2015).
1 2 3 |
data |
A set of configurational data as processable by the
|
outcome |
A character vector of outcomes. |
neg.out |
A logical vector specifying whether to negate outcomes. |
exo.facs |
A character vector with the names of the exogenous factors. |
tuples |
A numeric vector of tuples of exogenous factors to be created
from |
incl.cut1 |
The minimum sufficiency inclusion score for an output function value of "1". |
incl.cut0 |
The maximum sufficiency inclusion score for an output function value of "0". |
sol.type |
A character vector specifying the solution types to be generated. |
row.dom |
A logical vector imposing row dominance as a constraint on the solution to eliminate dominated inessential prime implicants. |
min.dis |
A logical vector imposing minimal disjunctivity as a constraint on the solution to eliminate models with more prime implicants than the model(s) with the fewest prime implicants. |
Model ambiguities are a common feature of configurational data analysis, although their extent often remains hidden because of confirmatory model selection or the use of computer programmes that cannot reveal their extent (Baumgartner and Thiem 2015; Thiem 2014)
This evaluation function computes the degree of ambiguity across variations of a reference design by recording the number of models for each design solution. It has initially been programmed for Baumgartner and Thiem (2015).
The argument data
requires a set of configurational data as processable by
the eQMC
function.
The argument outcome
is a character vector, specifying the outcome(s) to be analyzed, either in curly-bracket notation (e.g., O{value}
) if the outcome is from a multivalent (or a bivalent) factor, or in upper-case notation if the outcome is from a bivalent factor (e.g., O
as a short-cut for O{1}
). Outcomes from multivalent crisp-set factors always require curly-bracket notation. Outcomes can be single levels of factors not simultaneously passed to exo.facs
. At least one outcome has to be specified.
The argument neg.out
requires a logical vector of length one or two, whose values, which must not be duplicated, specify whether to negate the outcomes determined by outcome
. If an element in outcome
is a level from a multivalent factor, neg.out = TRUE
makes the disjunction of all remaining levels the outcome. Possible values for neg.out
include FALSE
, TRUE
, FALSE, TRUE
and TRUE, FALSE
.
The argument exo.facs
is a character vector with the names of the exogenous factors. If omitted, all factors in data
are used except that/those of the outcome/s given in outcome
. and tuples
specifies a numeric vector of tuples of exogenous factors to be created from exo.facs
.
Minterms with an inclusion score of at least incl.cut1
are coded positive (OUT = "1"
), minterms with an inclusion score below incl.cut1
but with at least incl.cut0
are coded as a contradiction (OUT = "C"
), and minterms with an inclusion score below incl.cut0
are coded negative (OUT = "0"
). If incl.cut0
is not explicitly changed, it is set equal to incl.cut1
.
The argument sol.type
requires a character vector specifying the solution types to be generated. For example, c("ps", "cs")
means parsimonious and conservative solution type.
The argument row.dom
requires a logical vector, and controls whether the principle of row dominance is imposed as a constraint on the solution. An inessential prime implicant P dominates another Q if all configurations covered by Q are also covered by P, but they are not interchangeable (cf. McCluskey 1956, 1425; McCluskey 1965, 164-152). If row dominance is operative, models that contain dominated prime implicants will not be returned.
The argument min.dis
requires a logical vector, and controls whether the principle of minimal disjunctivity is imposed as a constraint on the solution (McCluskey 1965, 12-126). If minimal disjunctivity is operative, models that contain more than the number of prime implicants of the model(s) with the fewest prime implicants will not be returned.
A list with the following two main components:
tuples |
A list of all tuples of exogenous factors of the respective size
taken from all factors given in |
n.models |
A list of matrices giving the number of models in each solution
for each design. The coding of labels has the following structure:
|
Thiem, Alrik | : development, documentation, programming, testing |
Alrik Thiem (Personal Website; ResearchGate Website)
Baumgartner, Michael, and Alrik Thiem. 2015. “Model Ambiguities in Configurational Comparative Research.” Sociological Methods & Research. Advance online publication. DOI: 10.1177/0049124115610351.
McCluskey, Edward J. 1956. “Minimization of Boolean Functions.” Bell Systems Technical Journal 35 (6):1417-44. DOI: 10.1002/j.1538-7305.1956.tb03835.x.
McCluskey, Edward J. 1965. Introduction to the Theory of Switching Circuits. Princeton: Princeton University Press.
Thiem, Alrik. 2014. “Navigating the Complexities of Qualitative Comparative Analysis: Case Numbers, Necessity Relations, and Model Ambiguities.” Evaluation Review 38 (6):487-513. DOI: 10.1177/0193841x14550863.
1 2 3 4 5 6 7 8 9 10 11 12 | ## Not run:
# load dataset
data(d.tumorscreen)
# designs: outcomes HPF and LPF; all 3 to 5-tuples of exogenous factors
designs <- ambiguity(d.tumorscreen, outcome = c("HPF", "LPF"),
neg.out = c(FALSE, TRUE), tuples = 3:5)
# share of solutions with ambiguities
mapply(function (x) round(colSums((x > 1)) / nrow(x), 2), designs$n.models)
## End(Not run)
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