Table 3 Rasch analyses of dimensionality and differential item functioning (DIF) for the overall WG-SS, ADL, IADL, and GALI indicators (recoded as binary variables, limited vs non-limited) (HSM survey)
HSM Survey | Fit with the one-dimensional Rasch model | Differential Item Functioning | |||
Overall fit p-value = 0.006, Person separation index = 0.79 | location | Chi square | P-value | Uniform DIF | Non-Uniform DIF |
WG-SS | -2.03 | 4.21 | 0.12 | – | – |
ADL | 1.86 | 8.83 | 0.01 | – | – |
IADL | 1.42 | 3.32 | 0.19 | – | – |
GALI | -1.26 | 5.20 | 0.07 | – | – |
ESPS 2012 Survey | Fit with the one-dimensional Rasch model | Differential Item Functioning | |||
Overall fit p-value = 0.00006, Person separation index = 0.68 | location | Chi square | P-value | Uniform DIF | Non-Uniform DIF |
WG-SS | -1.79 | 8.92 | 0.01 | age, education, occupation | – |
ADL | 2.13 | 3.99 | 0.14 | – | – |
IADL | 0.03 | 7.86 | 0.02 | age, education, occupation | – |
GALI | -0.37 | 12.36 | 0.002 | – | – |
ESPS 2014 Survey | Fit with the one-dimensional Rasch model | Differential Item Functioning | |||
Overall fit p-value = 0.00001, Person separation index = 0.72 | location | Chi square | P-value | Uniform DIF | Non-Uniform DIF |
WG-SS | -2.16 | 11.06 | 0.004 | – | – |
ADL | 2.59 | 3.00 | 0.22 | – | – |
IADL | 0.12 | 10.12 | 0.01 | – | – |
GALI | -0.55 | 12.76 | 0.002 | age | – |
Rasch analyses of dimensionality and differential item functioning (DIF) for the overall WG-SS, ADL, IADL, and GALI indicators (recoded as binary variables, limited vs non-limited) | |||||
HSM Survey | Fit with the one-dimensional Rasch model | Differential Item Functioning | |||
Overall fit p-value < 0.000001, Person separation index = 0.75 | location | Chi square | P-value | Uniform DIF | Non-Uniform DIF |
ADL | 1.08 | 14.18 | 0.0001 | – | – |
IADL | 0.76 | 11.52 | 0.001 | – | – |
GALI | -1.84 | 13.95 | 0.0002 | – | – |
ESPS 2012 Survey | Fit with the one-dimensional Rasch model | Differential Item Functioning | |||
Overall fit p-value = 0.007, Person separation index = 0.69 | location | Chi square | P-value | Uniform DIF | Non-Uniform DIF |
ADL | 1.43 | 96.19 | < 0.000001 | – | – |
IADL | -0.50 | 91.83 | < 0.000001 | – | – |
GALI | -0.93 | 47.48 | < 0.000001 | – | – |
ESPS 2014 Survey | Fit with the one-dimensional Rasch model | Differential Item Functioning | |||
Overall fit p-value = 0.0001, Person separation index = 0.72 | location | Chi square | P-value | Uniform DIF | Non-Uniform DIF |
ADL | 1.77 | 6.52 | 0.010 | – | – |
IADL | -0.55 | 8.73 | 0.003 | – | – |
GALI | -1.22 | 5.06 | 0.020 | age, education | – |