testCVPAT {cSEM}

Perform a Cross-Validated Predictive Ability Test (CVPAT)

Description

Usage

testCVPAT(
.object1              = NULL,
.object2              = NULL,
.approach_predict     = c("earliest", "direct"),
.seed                 = NULL,
.cv_folds             = 10,
.handle_inadmissibles = c("stop", "ignore"),
.testtype             = c("twosided", "onesided"))

Arguments

.object1

An R object of class cSEMResults resulting from a call to csem().

.object2

An R object of class cSEMResults resulting from a call to csem().

.approach_predict

Character string. Which approach should be used to predictions? One of "earliest" and "direct". If "earliest" predictions for indicators associated to endogenous constructs are performed using only indicators associated to exogenous constructs. If "direct", predictions for indicators associated to endogenous constructs are based on indicators associated to their direct antecedents. Defaults to "earliest".

.seed

Integer or NULL. The random seed to use. Defaults to NULL in which case an arbitrary seed is chosen. Note that the scope of the seed is limited to the body of the function it is used in. Hence, the global seed will not be altered!

.cv_folds

Integer. The number of cross-validation folds to use. Setting .cv_folds to N (the number of observations) produces leave-one-out cross-validation samples. Defaults to 10.

.handle_inadmissibles

Character string. How should inadmissible results be treated? One of "drop", "ignore", or "replace". If "drop", all replications/resamples yielding an inadmissible result will be dropped (i.e. the number of results returned will potentially be less than .R). For "ignore" all results are returned even if all or some of the replications yielded inadmissible results (i.e. number of results returned is equal to .R). For "replace" resampling continues until there are exactly .R admissible solutions. Depending on the frequency of inadmissible solutions this may significantly increase computing time. Defaults to "drop".

.testtype

Character string. One of "twosided" (H1: The models do not perform equally in predicting indicators belonging to endogenous constructs)" and onesided" (H1: Model 1 performs better in predicting indicators belonging to endogenous constructs than model2). Defaults to "twosided".

Details

Perform a Cross-Validated Predictive Ability Test (CVPAT) as described in (Liengaard et al. 2020). The predictive performance of two models based on the same dataset is compared. In doing so, the average difference in losses in predictions is compared for both models.

Value

An object of class cSEMCVPAT with print and plot methods. Technically, cSEMCVPAT is a named list containing the following list elements:

'$Information'

Additional information.

References

Liengaard BD, Sharma PN, Hult GTM, Jensen MB, Sarstedt M, Hair JF, Ringle CM (2020). “Prediction: Coveted, Yet Forsaken? Introducing a Cross-Validated Predictive Ability Test in Partial Least Squares Path Modeling.” Decision Sciences, 52(2), 362–392. doi:10.1111/deci.12445.

See Also

csem, cSEMResults, exportToExcel()

Examples

### Anime example taken from https://github.com/ISS-Analytics/pls-predict/

# Load data
data(Anime) # data is similar to the Anime.csv found on 
            # https://github.com/ISS-Analytics/pls-predict/ but with irrelevant
            # columns removed

# Split into training and data the same way as it is done on 
# https://github.com/ISS-Analytics/pls-predict/
set.seed(123)

index     <- sample.int(dim(Anime)[1], 83, replace = FALSE)
dat_train <- Anime[-index, ]
dat_test  <- Anime[index, ]

# Specify model
model <- "
# Structural model

ApproachAvoidance ~ PerceivedVisualComplexity + Arousal

# Measurement/composite model

ApproachAvoidance         =~ AA0 + AA1 + AA2 + AA3
PerceivedVisualComplexity <~ VX0 + VX1 + VX2 + VX3 + VX4
Arousal                   <~ Aro1 + Aro2 + Aro3 + Aro4
"

# Estimate (replicating the results of the `simplePLS()` function)
res <- csem(dat_train, 
            model, 
            .disattenuate = FALSE, # original PLS
            .iter_max = 300, 
            .tolerance = 1e-07, 
            .PLS_weight_scheme_inner = "factorial"
)

# Predict using a user-supplied training data set
pp <- predict(res, .test_data = dat_test)
pp

### Compute prediction metrics  ------------------------------------------------
res2 <- csem(Anime, # whole data set
            model, 
            .disattenuate = FALSE, # original PLS
            .iter_max = 300, 
            .tolerance = 1e-07, 
            .PLS_weight_scheme_inner = "factorial"
)

# Predict using 10-fold cross-validation
## Not run: 
pp2 <- predict(res, .benchmark = "lm")
pp2
## There is a plot method available
plot(pp2)
## End(Not run)

### Example using OrdPLScPredict -----------------------------------------------
# Transform the numerical indicators into factors
## Not run: 
data("BergamiBagozzi2000")
data_new <- data.frame(cei1    = as.ordered(BergamiBagozzi2000$cei1),
                       cei2    = as.ordered(BergamiBagozzi2000$cei2),
                       cei3    = as.ordered(BergamiBagozzi2000$cei3),
                       cei4    = as.ordered(BergamiBagozzi2000$cei4),
                       cei5    = as.ordered(BergamiBagozzi2000$cei5),
                       cei6    = as.ordered(BergamiBagozzi2000$cei6),
                       cei7    = as.ordered(BergamiBagozzi2000$cei7),
                       cei8    = as.ordered(BergamiBagozzi2000$cei8),
                       ma1     = as.ordered(BergamiBagozzi2000$ma1),
                       ma2     = as.ordered(BergamiBagozzi2000$ma2),
                       ma3     = as.ordered(BergamiBagozzi2000$ma3),
                       ma4     = as.ordered(BergamiBagozzi2000$ma4),
                       ma5     = as.ordered(BergamiBagozzi2000$ma5),
                       ma6     = as.ordered(BergamiBagozzi2000$ma6),
                       orgcmt1 = as.ordered(BergamiBagozzi2000$orgcmt1),
                       orgcmt2 = as.ordered(BergamiBagozzi2000$orgcmt2),
                       orgcmt3 = as.ordered(BergamiBagozzi2000$orgcmt3),
                       orgcmt5 = as.ordered(BergamiBagozzi2000$orgcmt5),
                       orgcmt6 = as.ordered(BergamiBagozzi2000$orgcmt6),
                       orgcmt7 = as.ordered(BergamiBagozzi2000$orgcmt7),
                       orgcmt8 = as.ordered(BergamiBagozzi2000$orgcmt8))

model <- "
# Measurement models
OrgPres =~ cei1 + cei2 + cei3 + cei4 + cei5 + cei6 + cei7 + cei8
OrgIden =~ ma1 + ma2 + ma3 + ma4 + ma5 + ma6
AffJoy  =~ orgcmt1 + orgcmt2 + orgcmt3 + orgcmt7
AffLove =~ orgcmt5 + orgcmt 6 + orgcmt8

# Structural model
OrgIden ~ OrgPres
AffLove ~ OrgIden
AffJoy  ~ OrgIden 
"
# Estimate using cSEM; note: the fact that indicators are factors triggers OrdPLSc
res <- csem(.model = model, .data = data_new[1:250,])
summarize(res)

# Predict using OrdPLSPredict
set.seed(123)
pred <- predict(
  .object = res, 
  .benchmark = "PLS-PM",
  .test_data = data_new[(251):305,],
   .treat_as_continuous = TRUE, .approach_score_target = "median"
  )

pred 
round(pred$Prediction_metrics[, -1], 4)
## End(Not run)