Table 4 Phase III (Steps 9 to 11) Reducing items per dimension

ABC-UI [31, 32]

AQL-5D [33,34,35,36,37,38,39]

IUI [40, 41]

OAB-5D [9, 36, 42,43,44]

EORTC-8D [7, 45,46,47,48]

QLU-C10D [49,50,51,52,53,54,55,56,57,58]

BUI [131]

HAQ-PBM, QLQ-PBM, MSIS-PB [61]

FACT-8D [62, 63]

CP-6D [66]

DEMQOL-U & -Proxy-U [8, 71,72,73,74]

AD-5D [75,76,77]

CARIES-QC-U [112]

DUI [78, 79]

DHP-3D & 5D [80]

HASMID-8 & 10 [81, 82]

DMD-QoL [134, 138, 139]

Step 9. Select Rasch or IRT model and fit model

 Rasch rating scale

X

X

X

 Rasch partial credit

X

X

X

X

 Unspecified polytymous Rasch

X

X

X

X

X

X

X

X

X

X

 Graded response IRT

 Response level ordering^a

X

X

X

X

X

X

X

X

X

X

X

X

X

 Meaningfulness of merged levels

 Item parameters at logit 0

X

X

X

X

X

X

X

X

X

 Global model fit – item-trait interaction^b

X

X

X

X

X

X

X

X

X

 Person separation index or person separation reliability^c

X

X

X

X

X

X

 Infit, Outfit

X

X

X

X

 Item fit residuals^d

X

X

X

X

X

X

X

X

X

 Local dependence

X

X

X

 Differential item functioning

X

X

X

X

X

X

X

X

X

X

X

X

X

X

 Person fit residuals^e

X

X

X

 Targeting of scale to persons

 Unidimensionality – principal components analysis of residuals, independent t-statistics

X

X

X

Step 10. Select items per dimension

 Item coverage across range of construct

X

X

X

X

X

X

 Floor and ceiling effects

X

X

X

X

X

X

X

X

X

 Missing data (%)

X

X

X

X

X

X

X

 Correlation of item to dimension

X

X

 Item importance and impact^f

HCP

P

P, HCP

P

X

Step 11. Model validation

 Expert validation

X

X

X

 Another data-set or split half

X

X

 Meaningful clinical rationale (face and content validity^f

HCP

HCP, P

HCP, R

HCP, R

R

P, G

HCP, P

HCP

 Alignment with parent psychometric instrument^{C, E, P}

X

X

NEWQoL-6D [84,85,86]

CORE-6D [88,89,90]

ReQoL-UI [91,92,93,94]

MobQoL-7D [95, 140]

MSIS-8D & -P [27, 97,98,99,100]

Neuro-QoL derived NQU [101, 102]

P-PBMSI [103,104,105,106]

MF-8D [107]

WAITe [108, 109]

POS-E [116]

MHOM RA [117]

Vis-QoL [118,119,120,121,122,123,124]

VFQ-UI [125,126,127,128,129,130]

MacNew-7D [87]

ECOHIS-4D [114]

PBI-WRQL [111]

PB-HIV [131]

CFQ-R-8 D [69]

Step 9. Select Rasch or IRT model and fit model

 Rasch rating scale

X

X

X

 Rasch partial credit

X

X

X

X

 Unspecified polytymous Rasch

X

X

X

X

X

X

X

X

X

 Graded response IRT

X

X

 Response level ordering^a

X

X

X

X

X

X

X

X

X

X

X

 Meaningfulness of merged levels

X

X

X

 Item parameters at logit 0

X

X

X

X

X

 Global model fit – item-trait interaction^b

X

X

X

X

X

X

X

X

X

X

X

X

 Person separation index or person separation reliability^c

X

X

X

X

X

X

X

X

X

X

X

 Infit, outfit

X

X

X

 Item fit residuals^d

X

X

X

X

X

X

X

X

X

X

X

 Local dependence

X

X

X

 Differential item functioning

X

X

X

X

X

X

X

X

X

X

 Person fit residuals^e

X

X

X

 Targeting of scale to persons

X

X

 Unidimensionality – principal components analysis of residuals, independent t-statistics

X

X

X

X

Step 10. Select items per dimension

 Item coverage across range of construct

X

X#

X

X

X

 Absence of floor and ceiling effects

X

X

X

X

X

 Percentage missing data

X

X

 Correlation of item to dimension

X

X

X

 Item importance and impact^e

PCA

Step 11. Model validation

 Expert validation

X

 Another data-set or split half

X

X

X

X

X

 Meaningful clinical rationale (face and content validity^e

P, HCP

HCP

P

P, HCP

X

 Alignment with parent psychometric instrument^{C, E, P}

X