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Table 1 Summary of Rasch measurement model on the PedsQL™ 3.0 Neuromuscular Module Indonesian Version parent proxy-report

From: Translation and validation of Indonesian version of Pediatric Quality of Life Inventory™ (PedsQL™) Neuromuscular Module

Parameter (with quality criteriaa) The PedsQL™ 3.0 Neuromuscular Module Indonesian Version
Total scale About My Child’s Neuromuscular Disease Subscale Communication Subscale About Our Family Resources Subscale
Model fit: summary of item     
Item mean in logits
(criteria: 0.0 logits)
0.0, SD = 0.48 0.0, SD = 0.54 0.0, SD = 0.23 0.0, SD = 0.53
Item reliability
(criteria: good 0.81–0.90; very good 0.91–0.94; excellent > 0.94)
0.93 0.94 0.15 0.90
Item separation
(criteria: > 3)
3.61 3.99 0.42 3.07
Item strata separated = [(4 × separation index) + 1] / 3
(criteria: fair, 2–3; good, 3–4; very good, 4–5; excellent, > 5)
5.15 \(\approx\) 5 levels 5.65 \(\approx\) 5 levels 0.89 \(\approx\) 1 level 4.43 \(\approx\) 4 levels
Item misfit MNSQ range extremes
(criteria: good 0.5–2.0; very good 0.7–1.4; excellent 0.77–1.3)
Infit: 0.68–1.41
Outfit: 0.51–1.81
Infit: 0.66–1.31
Outfit: 0.53–1.68
Infit: 0.66–1.49
Outfit: 0.63–1.35
Infit:0.72–1.45
Outfit: 0.72–1.35
Point measure correlation
(criteria: 0.4–0.85)
0.36–0.76 0.36–0.81 0.89–0.93 0.75–0.85
Model fit: summary of persons     
Person mean in logits
(criteria: 0.0 logits)
-1.13, SD = 1.31 -1.18, SD = 1.25 -1.63, SD = 2.42 -0.77, SD = 1.49
Person reliability
(criteria: good 0.81–0.90; very good 0.91–0.94; excellent > 0.94)
0.84 0.80 0.63 0.77
Person separation
(criteria: > 2)
2.32 1.99 1.31 1.84
Person strata separated = [(4 × separation index) + 1] / 3
(criteria: fair, 2–3; good, 3–4; very good, 4–5; excellent, > 5)
3.43 \(\approx\) 4 levels 2.99 \(\approx\) 3 levels 2.08 \(\approx\) 2 levels 2.67 \(\approx\) 3 levels
Cronbach alpha
(criteria: fair 0.67–0.80; good 0.81–0.90; very good 0.91–0.94; excellent > 0.94)
0.95 0.93 0.91 0.87
Dimensionality     
Raw variance in data explained by measures
(criteria > 40%)
51.9% 55.6% 55.6% 63.4%
Unexplained variance in 1st contrasts of PCA of residuals
(criteria: fair, 10–15%; good, 5–10%; very good, 3–5%; excellent, < 3%)
8.4% 10.0% 29.6% 11.9%
Rating scale analysis     
Average observed
(criteria: increases monotonically across rating scale)
Yes NA NA NA
Outfit MNSQ
(criteria: < 2 logits)
Yes NA NA NA
Adjacent threshold distance
(criteria: 1.4–5 logits)
(i) scale 0–1 was 0 to -0.09 = 0.09 logits; (ii)
scale 1–2 was -0.09 to -0.79 = 0.70 logits; (iii)
scale 2–3 was -0.79 to 0.71 = 1.50 logits; (iv)
scale 3–4 was 0.71 to 0.17 = 0.54 logits
NA NA NA
  1. SD: standard deviation; MNSQ: mean square; NA: not applicable
  2. aRating scale instrument quality criteria (Rasch Measurement Transactions 21, 1095, http://www.rasch.org/rmt/rmt211.pdf)