Blackbox / Basic Space scaling — morie_spatial_voting

Recovers respondent ideal points from an issue-scale response matrix via SVD on the column-centred matrix. Implements Poole's (1998) decomposition \(X_0 = \Psi W' + J_n c' + E_0\). Delegates to basicspace::blackbox when available.

Usage

morie_spatial_voting_blackbox(X, n_dims = 2L)

Arguments

X: A respondent-by-issue numeric matrix of responses (NA for missing).
n_dims: Number of dimensions to extract.

Value

A list with ideal_points, stimuli_weights, eigenvalues, singular_values, explained_variance, col_means, n_dims, and engine.

References

Poole, K. T. (1998); Armstrong et al. (2021).

Examples

set.seed(1)
X <- matrix(rnorm(30 * 6), 30, 6)
morie_spatial_voting_blackbox(X, n_dims = 2)
#> $ideal_points
#>              [,1]         [,2]
#>  [1,]  0.58085128 -0.826676185
#>  [2,] -0.44538833  0.095628158
#>  [3,] -0.02257064 -0.155435452
#>  [4,] -0.64196658 -0.286881879
#>  [5,] -0.87666292  0.363701355
#>  [6,] -0.47868528  0.112342734
#>  [7,] -0.05123051  0.720706499
#>  [8,] -0.21997769 -0.540136613
#>  [9,] -0.33995848 -0.495042509
#> [10,]  0.84889066 -0.505738306
#> [11,] -0.15343602 -0.217467933
#> [12,] -0.26258315  0.222831162
#> [13,]  0.36713540 -0.052204022
#> [14,]  0.62208999  0.592328247
#> [15,] -0.67657250  0.355709052
#> [16,]  0.64942730  0.342969537
#> [17,] -0.21200251  0.068297145
#> [18,] -0.58943621 -0.435397378
#> [19,] -0.20742489 -0.095639638
#> [20,] -0.22950946 -0.039318405
#> [21,]  0.72389459  0.210686184
#> [22,] -0.42822524  0.164932490
#> [23,]  0.33606493 -0.374773010
#> [24,] -0.01375499  1.035978485
#> [25,]  0.05081507 -0.601813924
#> [26,]  0.20454782 -0.504979894
#> [27,] -0.08816842 -0.003234797
#> [28,]  0.59455527  0.837512908
#> [29,]  0.50525307 -0.029684480
#> [30,]  0.45402847  0.040800468
#> 
#> $stimuli_weights
#>            [,1]       [,2]
#> [1,] -0.9363968 -0.8511332
#> [2,]  0.5169324 -1.3067813
#> [3,]  0.7234909 -1.6962691
#> [4,] -0.3580879 -0.0149343
#> [5,] -1.0094223  0.1549715
#> [6,]  1.9204472  0.6544508
#> 
#> $eigenvalues
#> [1] 42.28608 33.20040
#> 
#> $singular_values
#> [1] 6.502775 5.761979
#> 
#> $explained_variance
#> [1] 0.5051229
#> 
#> $col_means
#> [1]  0.08245817  0.13277458  0.11027803  0.11333276 -0.33002806  0.23700302
#> 
#> $n_dims
#> [1] 2
#> 
#> $engine
#> [1] "fallback"
#>