residuals-method {mirt}R Documentation

Compute model residuals

Description

Return model implied residuals for linear dependencies between items or at the person level. If the latent trait density was approximated (e.g., Davidian curves, Empirical histograms, etc) then passing use_dentype_estimate = TRUE will use the internally saved quadrature and density components (where applicable).

Usage

## S4 method for signature 'SingleGroupClass'
residuals(
  object,
  type = "LD",
  p.adjust = "none",
  df.p = FALSE,
  approx.z = FALSE,
  full.scores = FALSE,
  QMC = FALSE,
  printvalue = NULL,
  tables = FALSE,
  verbose = TRUE,
  Theta = NULL,
  suppress = NA,
  theta_lim = c(-6, 6),
  quadpts = NULL,
  fold = TRUE,
  upper = TRUE,
  technical = list(),
  ...
)

Arguments

object

an object of class SingleGroupClass or MultipleGroupClass. Bifactor models are automatically detected and utilized for better accuracy

type

type of residuals to be displayed. Can be either 'LD' or 'LDG2' for a local dependence matrix based on the X2 or G2 statistics (Chen & Thissen, 1997), 'Q3' for the statistic proposed by Yen (1984), 'JSI' for the jack-knife statistic proposed Edwards et al. (2018), 'exp' for the expected values for the frequencies of every response pattern, and 'expfull' for the expected values for every theoretically observable response pattern. For the 'LD' and 'LDG2' types, the upper diagonal elements represent the standardized residuals in the form of signed Cramers V coefficients

p.adjust

method to use for adjusting all p-values (see p.adjust for available options). Default is 'none'

df.p

logical; print the degrees of freedom and p-values?

approx.z

logical; transform \chi^2(df) information from LD tests into approximate z-ratios instead using the transformation z=\sqrt{2 * \chi^2} - \sqrt{2 * df - 1}?

full.scores

logical; compute relevant statistics for each subject in the original data?

QMC

logical; use quasi-Monte Carlo integration? If quadpts is omitted the default number of nodes is 5000

printvalue

a numeric value to be specified when using the res='exp' option. Only prints patterns that have standardized residuals greater than abs(printvalue). The default (NULL) prints all response patterns

tables

logical; for LD type, return the observed, expected, and standardized residual tables for each item combination?

verbose

logical; allow information to be printed to the console?

Theta

a matrix of factor scores used for statistics that require empirical estimates (i.e., Q3). If supplied, arguments typically passed to fscores() will be ignored and these values will be used instead

suppress

a numeric value indicating which parameter local dependency combinations to flag as being too high. Absolute values for the standardized estimates greater than this value will be returned, while all values less than this value will be set to NA

theta_lim

range for the integration grid

quadpts

number of quadrature nodes to use. The default is extracted from model (if available) or generated automatically if not available

fold

logical; apply the sum 'folding' described by Edwards et al. (2018) for the JSI statistic?

upper

logical; which portion of the matrix (upper versus lower triangle) should the suppress argument be applied to?

technical

list of technical arguments when models are re-estimated (see mirt for details)

...

additional arguments to be passed to fscores()

References

Chalmers, R., P. (2012). mirt: A Multidimensional Item Response Theory Package for the R Environment. Journal of Statistical Software, 48(6), 1-29. doi:10.18637/jss.v048.i06

Chen, W. H. & Thissen, D. (1997). Local dependence indices for item pairs using item response theory. Journal of Educational and Behavioral Statistics, 22, 265-289.

Edwards, M. C., Houts, C. R. & Cai, L. (2018). A Diagnostic Procedure to Detect Departures From Local Independence in Item Response Theory Models. Psychological Methods, 23, 138-149.

Yen, W. (1984). Effects of local item dependence on the fit and equating performance of the three parameter logistic model. Applied Psychological Measurement, 8, 125-145.

Examples

## No test: 

x <- mirt(Science, 1)
residuals(x)
## LD matrix (lower triangle) and standardized values.
## 
## Upper triangle summary:
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##  -0.147  -0.136  -0.111  -0.045   0.041   0.152 
## 
##         Comfort   Work Future Benefit
## Comfort      NA -0.147 -0.101   0.152
## Work     25.512     NA  0.088  -0.141
## Future   12.002  9.208     NA  -0.122
## Benefit  27.321 23.235 17.461      NA
residuals(x, tables = TRUE)
## $Comfort_Work
## $Comfort_Work$Obs
##    
##       1   2   3   4
##   1   2   0   1   2
##   2   2  11  15   4
##   3  24  71 148  23
##   4   5  16  42  26
## 
## $Comfort_Work$Exp
##           [,1]      [,2]       [,3]      [,4]
## [1,]  1.046123  1.787854   1.922925  0.262908
## [2,]  5.722535 11.386923  13.625623  1.972172
## [3,] 23.322258 69.348472 140.029013 31.718143
## [4,]  3.487224 14.109434  50.763258 21.495135
## 
## $Comfort_Work$std_res
##    
##              1          2          3          4
##   1  0.9326115 -1.3371066 -0.6655567  3.3878247
##   2 -1.5561252 -0.1146625  0.3723298  1.4439717
##   3  0.1403392  0.1983204  0.6736015 -1.5479971
##   4  0.8100928  0.5033119 -1.2299596  0.9716541
## 
## 
## $Comfort_Future
## $Comfort_Future$Obs
##    
##       1   2   3   4
##   1   2   2   1   0
##   2   3  11  11   7
##   3   8  51 155  52
##   4   1   8  43  37
## 
## $Comfort_Future$Exp
##           [,1]      [,2]       [,3]       [,4]
## [1,] 0.7680477  1.812936   2.091572  0.3472546
## [2,] 3.6749826 11.241583  15.084907  2.7057791
## [3,] 9.1976778 52.384929 148.579175 54.2561060
## [4,] 0.7527106  6.828614  42.541147 39.7325783
## 
## $Comfort_Future$std_res
##    
##               1           2           3           4
##   1  1.40572316  0.13893088 -0.75477217 -0.58928310
##   2 -0.35209910 -0.07205318 -1.05174604  2.61058722
##   3 -0.39491253 -0.19134814  0.52675890 -0.30629167
##   4  0.28503062  0.44826372  0.07035076 -0.43351011
## 
## 
## $Comfort_Benefit
## $Comfort_Benefit$Obs
##    
##       1   2   3   4
##   1   4   0   1   0
##   2   5  10  13   4
##   3  11  81 133  41
##   4   1   9  46  33
## 
## $Comfort_Benefit$Exp
##            [,1]     [,2]       [,3]       [,4]
## [1,]  0.6710457  1.95217   1.959779  0.4368153
## [2,]  3.6241191 12.16983  13.682082  3.2312240
## [3,] 14.8454892 71.28246 131.343241 46.9466978
## [4,]  2.3173267 14.55596  44.803655 28.1781067
## 
## $Comfort_Benefit$std_res
##    
##              1          2          3          4
##   1  4.0637950 -1.3972006 -0.6855953 -0.6609200
##   2  0.7227359 -0.6219892 -0.1844000  0.4276774
##   3 -0.9980547  1.1509727  0.1445624 -0.8679073
##   4 -0.8653661 -1.4562597  0.1787310  0.9083677
## 
## 
## $Work_Future
## $Work_Future$Obs
##    
##       1   2   3   4
##   1   7  10  14   2
##   2   3  28  57  10
##   3   3  31 122  50
##   4   1   3  17  34
## 
## $Work_Future$Exp
##           [,1]      [,2]      [,3]      [,4]
## [1,] 4.6004355 12.483087  14.34426  2.150355
## [2,] 5.8020446 27.786418  52.26417 10.780046
## [3,] 3.6903551 28.936581 118.01439 55.699488
## [4,] 0.3005835  3.061977  23.67397 28.411829
## 
## $Work_Future$std_res
##    
##               1           2           3           4
##   1  1.11874979 -0.70279865 -0.09089724 -0.10253275
##   2 -1.16328067  0.04051800  0.65507895 -0.23757996
##   3 -0.35936723  0.38358699  0.36688237 -0.76367799
##   4  1.27571400 -0.03541829 -1.37166696  1.04838334
## 
## 
## $Work_Benefit
## $Work_Benefit$Obs
##    
##       1   2   3   4
##   1   4   8  12   9
##   2   6  34  47  11
##   3   8  52 111  35
##   4   3   6  23  23
## 
## $Work_Benefit$Exp
##          [,1]      [,2]      [,3]      [,4]
## [1,] 4.233251 13.170723  13.31610  2.858063
## [2,] 7.660483 32.196149  44.96112 11.814929
## [3,] 8.417022 46.931424 106.55195 44.440425
## [4,] 1.147224  7.662122  26.95958 19.679427
## 
## $Work_Benefit$std_res
##    
##              1          2          3          4
##   1 -0.1133671 -1.4247756 -0.3606627  3.6330344
##   2 -0.5999380  0.3179060  0.3040694 -0.2370851
##   3 -0.1437407  0.7398678  0.4309125 -1.4161278
##   4  1.7298113 -0.6004660 -0.7625934  0.7485258
## 
## 
## $Future_Benefit
## $Future_Benefit$Obs
##    
##       1   2   3   4
##   1   5   1   6   2
##   2   5  32  30   5
##   3   8  53 118  31
##   4   3  14  39  40
## 
## $Future_Benefit$Exp
##          [,1]      [,2]       [,3]       [,4]
## [1,] 2.960508  6.706374   4.143629  0.5829072
## [2,] 7.760422 29.142832  29.887302  5.4775063
## [3,] 9.227453 52.779344 109.948223 36.3417805
## [4,] 1.509597 11.331867  47.809604 36.3906499
## 
## $Future_Benefit$std_res
##    
##               1           2           3           4
##   1  1.18532911 -2.20351681  0.91195681  1.85608815
##   2 -0.99090687  0.52926095  0.02061456 -0.20402700
##   3 -0.40407692  0.03037266  0.76788760 -0.88610042
##   4  1.21303423  0.79260501 -1.27408623  0.59832081
residuals(x, type = 'exp')
##    Comfort Work Future Benefit freq    exp std.res
## 1        1    1      1       1    2  0.124   5.324
## 2        1    3      2       1    1  0.067   3.605
## 3        1    4      2       3    1  0.019   7.046
## 4        1    4      3       1    1  0.006  12.642
## 5        2    1      1       1    1  0.460   0.796
## 6        2    1      2       4    1  0.095   2.930
## 7        2    2      1       1    1  0.351   1.095
## 8        2    2      2       2    4  2.147   1.264
## 9        2    2      2       3    2  1.616   0.302
## 10       2    2      3       1    1  0.377   1.015
## 11       2    2      3       2    1  1.716  -0.547
## 12       2    2      3       3    1  2.228  -0.823
## 13       2    2      4       3    1  0.251   1.497
## 14       2    3      1       3    1  0.213   1.707
## 15       2    3      2       2    2  1.545   0.366
## 16       2    3      2       3    1  1.489  -0.401
## 17       2    3      3       2    3  2.248   0.502
## 18       2    3      3       3    3  3.910  -0.460
## 19       2    3      3       4    2  1.035   0.948
## 20       2    3      4       1    1  0.041   4.763
## 21       2    3      4       3    2  0.866   1.218
## 22       2    4      2       1    1  0.029   5.690
## 23       2    4      4       3    2  0.259   3.418
## 24       2    4      4       4    1  0.184   1.902
## 25       3    1      1       1    1  0.644   0.444
## 26       3    1      1       3    2  0.638   1.705
## 27       3    1      2       2    2  3.923  -0.971
## 28       3    1      2       3    4  3.077   0.526
## 29       3    1      3       2    5  3.567   0.759
## 30       3    1      3       3    5  5.097  -0.043
## 31       3    1      3       4    3  1.160   1.709
## 32       3    1      4       3    1  0.764   0.269
## 33       3    1      4       4    1  0.320   1.203
## 34       3    2      1       2    1  1.781  -0.585
## 35       3    2      1       4    1  0.154   2.157
## 36       3    2      2       1    1  2.250  -0.833
## 37       3    2      2       2   10  8.471   0.525
## 38       3    2      2       3    7  8.067  -0.376
## 39       3    2      3       1    1  2.221  -0.819
## 40       3    2      3       2   16 11.743   1.242
## 41       3    2      3       3   22 19.584   0.546
## 42       3    2      3       4    5  4.950   0.023
## 43       3    2      4       1    1  0.193   1.835
## 44       3    2      4       2    1  1.293  -0.258
## 45       3    2      4       3    3  3.778  -0.400
## 46       3    2      4       4    2  1.716   0.217
## 47       3    3      1       3    2  0.971   1.044
## 48       3    3      2       1    1  1.764  -0.575
## 49       3    3      2       2   13  7.852   1.837
## 50       3    3      2       3   10  9.780   0.070
## 51       3    3      2       4    2  1.975   0.018
## 52       3    3      3       1    5  3.363   0.893
## 53       3    3      3       2   23 20.447   0.565
## 54       3    3      3       3   52 45.243   1.005
## 55       3    3      3       4    8 14.757  -1.759
## 56       3    3      4       2    7  4.389   1.246
## 57       3    3      4       3   13 16.979  -0.966
## 58       3    3      4       4   12 10.323   0.522
## 59       3    4      1       3    1  0.090   3.030
## 60       3    4      2       3    1  1.098  -0.093
## 61       3    4      3       2    2  3.043  -0.598
## 62       3    4      3       3    4  8.562  -1.559
## 63       3    4      3       4    4  3.637   0.191
## 64       3    4      4       1    1  0.160   2.100
## 65       3    4      4       2    1  1.287  -0.253
## 66       3    4      4       3    6  6.466  -0.183
## 67       3    4      4       4    3  5.659  -1.118
## 68       4    1      1       4    1  0.006  12.587
## 69       4    1      2       2    1  0.325   1.183
## 70       4    1      2       4    2  0.057   8.158
## 71       4    1      3       4    1  0.300   1.278
## 72       4    2      2       1    1  0.193   1.836
## 73       4    2      2       3    3  1.017   1.967
## 74       4    2      3       3    8  4.462   1.675
## 75       4    2      3       4    2  1.448   0.459
## 76       4    2      4       2    1  0.433   0.862
## 77       4    2      4       4    1  1.080  -0.077
## 78       4    3      2       3    1  1.665  -0.516
## 79       4    3      3       2    2  4.874  -1.302
## 80       4    3      3       3   21 14.002   1.870
## 81       4    3      3       4    3  5.965  -1.214
## 82       4    3      4       2    2  2.097  -0.067
## 83       4    3      4       3    5 10.419  -1.679
## 84       4    3      4       4    8  8.830  -0.279
## 85       4    4      3       2    1  0.966   0.034
## 86       4    4      3       3    2  3.571  -0.831
## 87       4    4      3       4    3  2.063   0.652
## 88       4    4      4       2    2  0.906   1.149
## 89       4    4      4       3    6  5.780   0.092
## 90       4    4      4       4   12  7.470   1.657
residuals(x, suppress = .15)
## LD matrix (lower triangle) and standardized values.
## 
## Upper triangle summary:
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##  -0.147  -0.136  -0.111  -0.045   0.041   0.152 
## 
##         Comfort Work Future Benefit
## Comfort      NA   NA     NA   0.152
## Work         NA   NA     NA      NA
## Future       NA   NA     NA      NA
## Benefit  27.321   NA     NA      NA
residuals(x, df.p = TRUE)
## Degrees of freedom (lower triangle) and p-values:
## 
##         Comfort  Work Future Benefit
## Comfort      NA 0.002  0.213   0.001
## Work          9    NA  0.418   0.006
## Future        9 9.000     NA   0.042
## Benefit       9 9.000  9.000      NA
## 
## LD matrix (lower triangle) and standardized values.
## 
## Upper triangle summary:
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##  -0.147  -0.136  -0.111  -0.045   0.041   0.152 
## 
##         Comfort   Work Future Benefit
## Comfort      NA -0.147 -0.101   0.152
## Work     25.512     NA  0.088  -0.141
## Future   12.002  9.208     NA  -0.122
## Benefit  27.321 23.235 17.461      NA
residuals(x, df.p = TRUE, p.adjust = 'fdr') # apply FWE control
## Degrees of freedom (lower triangle) and p-values:
## 
##         Comfort  Work Future Benefit
## Comfort      NA 0.007  0.256   0.007
## Work          9    NA  0.418   0.011
## Future        9 9.000     NA   0.063
## Benefit       9 9.000  9.000      NA
## 
## LD matrix (lower triangle) and standardized values.
## 
## Upper triangle summary:
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##  -0.147  -0.136  -0.111  -0.045   0.041   0.152 
## 
##         Comfort   Work Future Benefit
## Comfort      NA -0.147 -0.101   0.152
## Work     25.512     NA  0.088  -0.141
## Future   12.002  9.208     NA  -0.122
## Benefit  27.321 23.235 17.461      NA
# Pearson's X2 estimate for goodness-of-fit
full_table <- residuals(x, type = 'expfull')
head(full_table)
##   Comfort Work Future Benefit freq   exp    res
## 1       1    1      1       1    2 0.124  5.324
## 2       1    1      1       2    0 0.160 -0.400
## 3       1    1      1       3    0 0.054 -0.233
## 4       1    1      1       4    0 0.005 -0.073
## 5       1    1      2       1    0 0.092 -0.303
## 6       1    1      2       2    0 0.219 -0.468
X2 <- with(full_table, sum((freq - exp)^2 / exp))
df <- nrow(full_table) - extract.mirt(x, 'nest') - 1
p <- pchisq(X2, df = df, lower.tail=FALSE)
data.frame(X2, df, p, row.names='Pearson-X2')
##                  X2  df            p
## Pearson-X2 689.3347 239 2.942933e-45
# above FOG test as a function
PearsonX2 <- function(x){
   full_table <- residuals(x, type = 'expfull')
   X2 <- with(full_table, sum((freq - exp)^2 / exp))
   df <- nrow(full_table) - extract.mirt(x, 'nest') - 1
   p <- pchisq(X2, df = df, lower.tail=FALSE)
   data.frame(X2, df, p, row.names='Pearson-X2')
}
PearsonX2(x)
##                  X2  df            p
## Pearson-X2 689.3347 239 2.942933e-45
# extract results manually
out <- residuals(x, df.p = TRUE, verbose=FALSE)
str(out)
## List of 2
##  $ df.p: 'mirt_matrix' num [1:4, 1:4] NA 9 9 9 0.00245 ...
##   ..- attr(*, "dimnames")=List of 2
##   .. ..$ : chr [1:4] "Comfort" "Work" "Future" "Benefit"
##   .. ..$ : chr [1:4] "Comfort" "Work" "Future" "Benefit"
##  $ LD  : 'mirt_matrix' num [1:4, 1:4] NA 25.512 12.002 27.321 -0.147 ...
##   ..- attr(*, "dimnames")=List of 2
##   .. ..$ : chr [1:4] "Comfort" "Work" "Future" "Benefit"
##   .. ..$ : chr [1:4] "Comfort" "Work" "Future" "Benefit"
out$df.p[1,2]
## [1] 0.002454207
# with and without supplied factor scores
Theta <- fscores(x)
residuals(x, type = 'Q3', Theta=Theta)
## Q3 summary statistics:
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##  -0.320  -0.249  -0.225  -0.190  -0.205   0.085 
## 
##         Comfort   Work Future Benefit
## Comfort   1.000 -0.203 -0.252   0.085
## Work     -0.203  1.000 -0.208  -0.242
## Future   -0.252 -0.208  1.000  -0.320
## Benefit   0.085 -0.242 -0.320   1.000
residuals(x, type = 'Q3', method = 'ML')
## Q3 summary statistics:
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##  -0.514  -0.426  -0.357  -0.311  -0.270   0.053 
## 
##         Comfort   Work Future Benefit
## Comfort   1.000 -0.262 -0.419   0.053
## Work     -0.262  1.000 -0.428  -0.295
## Future   -0.419 -0.428  1.000  -0.514
## Benefit   0.053 -0.295 -0.514   1.000
# Edwards et al. (2018) JSI statistic
N <- 250
a <- rnorm(10, 1.7, 0.3)
d <- rnorm(10)
dat <- simdata(a, d, N=250, itemtype = '2PL')

mod <- mirt(dat, 1)
residuals(mod, type = 'JSI')
## JSI summary statistics:
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##  -0.882  -0.294  -0.040   0.000   0.315   1.029
##         Item_1 Item_2 Item_3 Item_4 Item_5 Item_6 Item_7 Item_8 Item_9 Item_10
## Item_1      NA -0.189 -0.455 -0.294 -0.133  0.627  0.252  0.535 -0.625   0.562
## Item_2  -0.189     NA  0.150  1.029  0.148 -0.099 -0.377 -0.513  0.329  -0.329
## Item_3  -0.455  0.150     NA -0.618  0.188 -0.100 -0.136 -0.448  1.004   0.315
## Item_4  -0.294  1.029 -0.618     NA  0.113  0.074 -0.040  0.502 -0.129  -0.882
## Item_5  -0.133  0.148  0.188  0.113     NA -0.056 -0.035 -0.600 -0.145   0.326
## Item_6   0.627 -0.099 -0.100  0.074 -0.056     NA -0.126  0.405 -0.577  -0.180
## Item_7   0.252 -0.377 -0.136 -0.040 -0.035 -0.126     NA  0.214  0.334   0.060
## Item_8   0.535 -0.513 -0.448  0.502 -0.600  0.405  0.214     NA -0.647   0.237
## Item_9  -0.625  0.329  1.004 -0.129 -0.145 -0.577  0.334 -0.647     NA   0.342
## Item_10  0.562 -0.329  0.315 -0.882  0.326 -0.180  0.060  0.237  0.342      NA
residuals(mod, type = 'JSI', fold=FALSE) # unfolded
## JSI summary statistics:
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##  -0.489  -0.148  -0.019   0.000   0.136   0.530
##         Item_1 Item_2 Item_3 Item_4 Item_5 Item_6 Item_7 Item_8 Item_9 Item_10
## Item_1      NA -0.128 -0.203 -0.145 -0.057  0.367  0.119  0.350 -0.342   0.290
## Item_2  -0.061     NA  0.066  0.499  0.076 -0.042 -0.183 -0.322  0.170  -0.150
## Item_3  -0.252  0.084     NA -0.253  0.120 -0.033 -0.068 -0.184  0.507   0.137
## Item_4  -0.149  0.530 -0.365     NA  0.057  0.019 -0.023  0.268 -0.090  -0.489
## Item_5  -0.076  0.072  0.068  0.056     NA -0.044 -0.014 -0.273 -0.081   0.124
## Item_6   0.260 -0.058 -0.067  0.055 -0.012     NA -0.080  0.327 -0.338  -0.145
## Item_7   0.133 -0.194 -0.068 -0.018 -0.021 -0.047     NA  0.092  0.158   0.028
## Item_8   0.184 -0.191 -0.265  0.233 -0.327  0.079  0.122     NA -0.337   0.042
## Item_9  -0.284  0.159  0.497 -0.039 -0.063 -0.239  0.176 -0.310     NA   0.176
## Item_10  0.272 -0.179  0.178 -0.393  0.202 -0.036  0.032  0.195  0.166      NA
# LD between items 1-2
aLD <- numeric(10)
aLD[1:2] <- rnorm(2, 2.55, 0.15)
a2 <- cbind(a, aLD)
dat <- simdata(a2, d, N=250, itemtype = '2PL')

mod <- mirt(dat, 1)

# JSI executed in parallel over multiple cores
if(interactive()) mirtCluster()
residuals(mod, type = 'JSI')
## JSI summary statistics:
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##  -1.019  -0.349  -0.110  -0.008   0.329   1.728
##         Item_1 Item_2 Item_3 Item_4 Item_5 Item_6 Item_7 Item_8 Item_9 Item_10
## Item_1      NA  1.728  0.090  0.027 -0.088 -1.019 -0.581  0.130 -0.205  -0.133
## Item_2   1.728     NA  0.356  0.377 -0.172 -0.979 -0.122 -0.181 -0.318  -0.591
## Item_3   0.090  0.356     NA  0.377 -0.562 -0.349 -0.189 -0.283  0.032   0.994
## Item_4   0.027  0.377  0.377     NA  0.277 -0.389  0.740 -0.795 -0.018  -0.400
## Item_5  -0.088 -0.172 -0.562  0.277     NA -0.300  0.541 -0.010  0.224  -0.110
## Item_6  -1.019 -0.979 -0.349 -0.389 -0.300     NA  0.001  0.480  1.659   0.630
## Item_7  -0.581 -0.122 -0.189  0.740  0.541  0.001     NA  0.329 -0.220  -0.805
## Item_8   0.130 -0.181 -0.283 -0.795 -0.010  0.480  0.329     NA -0.637   0.731
## Item_9  -0.205 -0.318  0.032 -0.018  0.224  1.659 -0.220 -0.637     NA  -0.640
## Item_10 -0.133 -0.591  0.994 -0.400 -0.110  0.630 -0.805  0.731 -0.640      NA
## End(No test)

[Package mirt version 1.40 Index]