Qualifying conditions for patient recruitment.

PurposeWe aimed to (1) establish linguistic and ethnic equivalence (i.e. lack of bias) for the items in the English and Chinese versions of the Singapore Health and Well Being (SHAWS) Physical Functioning (PF), Positive Mindset (PM) and Social Relationship (SR) item banks (IBs); and (2) evaluate the preliminary efficiency of these IBs using Computer Adaptive Testing (CAT) simulations.MethodsIn this cross-sectional study, 671, 670, and 672 subjects answered 55, 48 and 30 items of the PF, PM, and SR IBs, respectively. Rasch analysis was conducted to assess each IB’s psychometric properties, particularly the presence of differential item functioning (DIF) for language and ethnicity. A set of performance criteria related to removing items that displayed notable DIF were employed. CAT simulations determined the mean number of items for high, moderate, and moderate-low measurement precisions (stopping rule: SEM 0.300, 0.387. 0.521, respectively).ResultsHalf of subjects were >50 years old (40.9% PF, 42.1% PM, 41.4% SR), Chinese (50.7% PF, 51.0% PM, 50.6% SR) and female (50.0% PF. 49.4% PM, 52.8% SR) respectively. Rasch analysis revealed 4 items with DIF for the PF IB, 9 items with DIF for the PM IB and 2 items with DIF for the SR IB. In CAT simulations, the mean number of items administered was 8.5, 21.6 and 14.5 for the PF, PM and SR IBs, respectively (SEM 0.300), 5.1, 13.0, 8.0 for PF, PM and SR IBs, respectively (SEM 0.387) and 3.1, 5.3 and 4.1 for PF, PM and SR IBs, respectively (SEM 0.521).ConclusionThe PF, PM and SR IBs to measure health-related quality of life revealed minimal DIF for language and ethnicity after remedial efforts. CAT simulations demonstrated that these IBs were efficient, especially when the stopping rule was set at moderate precision, and support the implementation of the SHAWS IBs into routine clinical care.</div

Simulation results for <i>social relationship</i> at three different precision stopping rule estimates across deciles of participant ability level.

Simulation results for social relationship at three different precision stopping rule estimates across deciles of participant ability level.</p

S1 Data -

PurposeWe aimed to (1) establish linguistic and ethnic equivalence (i.e. lack of bias) for the items in the English and Chinese versions of the Singapore Health and Well Being (SHAWS) Physical Functioning (PF), Positive Mindset (PM) and Social Relationship (SR) item banks (IBs); and (2) evaluate the preliminary efficiency of these IBs using Computer Adaptive Testing (CAT) simulations.MethodsIn this cross-sectional study, 671, 670, and 672 subjects answered 55, 48 and 30 items of the PF, PM, and SR IBs, respectively. Rasch analysis was conducted to assess each IB’s psychometric properties, particularly the presence of differential item functioning (DIF) for language and ethnicity. A set of performance criteria related to removing items that displayed notable DIF were employed. CAT simulations determined the mean number of items for high, moderate, and moderate-low measurement precisions (stopping rule: SEM 0.300, 0.387. 0.521, respectively).ResultsHalf of subjects were >50 years old (40.9% PF, 42.1% PM, 41.4% SR), Chinese (50.7% PF, 51.0% PM, 50.6% SR) and female (50.0% PF. 49.4% PM, 52.8% SR) respectively. Rasch analysis revealed 4 items with DIF for the PF IB, 9 items with DIF for the PM IB and 2 items with DIF for the SR IB. In CAT simulations, the mean number of items administered was 8.5, 21.6 and 14.5 for the PF, PM and SR IBs, respectively (SEM 0.300), 5.1, 13.0, 8.0 for PF, PM and SR IBs, respectively (SEM 0.387) and 3.1, 5.3 and 4.1 for PF, PM and SR IBs, respectively (SEM 0.521).ConclusionThe PF, PM and SR IBs to measure health-related quality of life revealed minimal DIF for language and ethnicity after remedial efforts. CAT simulations demonstrated that these IBs were efficient, especially when the stopping rule was set at moderate precision, and support the implementation of the SHAWS IBs into routine clinical care.</div

CAT simulation results for the physical function, positive mindset, and social relationship item banks.

CAT simulation results for the physical function, positive mindset, and social relationship item banks.</p

Simulation results for <i>positive mindset</i> at three different precision stopping rule estimates across deciles of participant ability level.

Simulation results for positive mindset at three different precision stopping rule estimates across deciles of participant ability level.</p

VisQoL utility scores by better or worse eye category and per vision state (by VA category).

<p>VA = visual acuity, VisQoL = Vision and Quality of Life Index, *indicates significant difference (p≤0.001) between categories using post-hoc Bonferroni testing following ANCOVA. Bolded data correspond to the 6 vision states relating to combined categories of VI in the better and worse seeing eyes.</p

Simulation results <i>physical functioning</i> at three different precision stopping rule estimates across deciles of participant ability level.

Simulation results physical functioning at three different precision stopping rule estimates across deciles of participant ability level.</p

Sociodemographic characteristics of the study subjects.

Sociodemographic characteristics of the study subjects.</p

Differential item functioning (DIF) for ethnicity and language for the physical functioning, positive mindset, and social relationship item banks.

Differential item functioning (DIF) for ethnicity and language for the physical functioning, positive mindset, and social relationship item banks.</p

Utility across all six vision states (VS), for the VisQoL and the EQ-5D utility instruments, demonstrating a reduction of visual acuity with worsening vision states for the VisQoL but not the EQ-5D.

<p>Utility across all six vision states (VS), for the VisQoL and the EQ-5D utility instruments, demonstrating a reduction of visual acuity with worsening vision states for the VisQoL but not the EQ-5D.</p