Skip to main content

Table 4 Using Rasch analysis with rating scale model in differential item functioning analysis

From: Measurement equivalence and feasibility of the EORTC QLQ-PR25: paper-and-pencil versus touch-screen administration

  EORTC QLQ-PR25 Paper Computer Differential item functioning
  Items ranked by difficulty Difficulty SE Difficulty SE Difficulty SE p-value
Urinary symptoms (US) a        
US37 Painful voiding (least frequent) −3.055 0.369 −2.790 0.321 −0.266 0.489 0.588
US39 Limitation of daily activities because of US −1.035 0.250 −1.306 0.251 0.271 0.354 0.445
US36 Urinary incontinence −0.199 0.225 −0.349 0.226 0.150 0.319 0.638
US35 Need to remain close to toilet −0.149 0.223 −0.346 0.226 0.197 0.318 0.536
US31 Urinary frequency in daytime 0.599 0.210 1.261 0.200 −0.662 0.290 0.024
US34 Sleep deprivation because of US 1.118 0.206 0.766 0.207 0.352 0.292 0.229
US33 Urinary urgency 1.118 0.206 1.420 0.198 −0.302 0.286 0.292
US32 Nocturia (most frequent) 1.537 0.204 1.301 0.199 0.236 0.285 0.410
Bowel symptoms (BS) a        
BS42 Fecal blood (least frequent) −0.656 0.413 −0.839 0.404 0.183 0.578 0.752
BS41 Fecal incontinence −0.656 0.413 −0.535 0.377 −0.120 0.559 0.830
BS40 Limitation of daily activities because of BS 0.437 0.339 0.313 0.328 0.124 0.472 0.793
BS43 Bloated feeling (most frequent) 0.879 0.327 1.026 0.315 −0.147 0.454 0.747
Treatment-related symptoms (TS) a        
TS45 Breast tenderness (least frequent) −1.676 0.384 −1.489 0.381 −0.187 0.541 0.731
TS46 Swelling in legs or ankles −0.449 0.257 −0.151 0.247 −0.298 0.357 0.406
TS44 Hot flushes −0.384 0.253 −0.812 0.301 0.429 0.393 0.277
TS47 Bother due to weight loss −0.035 0.234 0.284 0.221 −0.320 0.322 0.322
TS48 Bother due to weight gain 0.668 0.200 0.515 0.209 0.153 0.289 0.598
TS49 Felt less masculine (most frequent) 1.756 0.165 1.677 0.167 0.078 0.235 0.739
Sexual activity (SX) b        
SX50 Sexual interest (more likely) −0.977 0.334 −1.338 0.315 0.362 0.459 0.432
SX51 Sexual activity (less likely) 0.968 0.344 1.359 0.330 −0.391 0.477 0.414
Sexual functioning (SX) b,c        
SX55 Sexual comfort (more likely) −1.945 0.303 −1.408 0.270 −0.537 0.406 0.189
SX54 No ejaculation problems −0.607 0.228 −0.257 0.220 −0.350 0.316 0.272
SX53 No erectile problems −0.047 0.210 −0.047 0.214 0.000 0.299 1.000
SX52 Sexual enjoyment (less likely) 2.441 0.220 1.888 0.192 0.552 0.292 0.061
  1. aRaw responses: 1: Very much; 2: Quite a bit; 3: A little; 4: Not at all, higher score means less frequent symptom.
  2. bRaw responses: 4: Very much; 3: Quite a bit; 2: A little; 1: Not at all, higher score means more activity/functioning.
  3. cSexual functioning items are conditional and only applicable to those being sexually active. A total of 48 patients reported being sexually active in this study.
  4. Difficulty: Item difficulty, higher difficulty means worse HRQOL/more frequent symptom.