Background
Content development
Instrument (acronym) [reference] | Number of items |
---|---|
Arthritic Impact Measurement Scales (1 & 2) (AIMS) [42] | 150 |
Beck Depression Inventory (BDI) [53] | 21 |
Cancer Rehabilitation Evaluation System (CARES) [54] | 140 |
Center for Epidemiologic Studies – Depressed Mood Scale (CES-D) [43] | 20 |
Clinical Back Pain Questionnaire (CBPQ) [55] | 19 |
Disabilities of the Arm, Shoulder and Hand (DASH) [56] | 68 |
Disability Rating Index (DRI) [57] | 12 |
EORTC Quality of Life Questionnaire – C30 (EORTC) [58] | 30 |
EuroQol (EQ-5D) [17] | 5 |
Functional Assessment of Cancer Therapy Scales (FACT) [41] | 177 |
Functional Living Index: Cancer (FLIC) [59] | 22 |
General Health Questionnaire (GHQ) [60] | 28 |
Health Utilities Index, Mark 2 (HUI2) [16] | 7 |
Health Utilities Index, Mark 3 (HUI3) [16] | 8 |
Musculoskeletal Functional Assessment Instrument (MFAI) [61] | 120 |
McMaster Toronto Arthritis Patient Preference Disability Questionnaire (MACTAR) [62] | 5 |
McMaster Health Index Questionnaire (MHIQ) [63] | 74 |
Michigan Hand Outcomes Questionnaire (MHOQ) [64] | 37 |
90 S Short Form-36 Health Survey (SF-36) [15] | 36 |
Multidimensional Health Assessment Questionnaire (MDHAQ) [65] | 9 |
National Population Health Survey Questionnaire (NPHS) [66] | 10 |
North American Spine Society Low Back Pain Outcome Instrument (NASS) [67] | 46 |
Nottingham Health Profile, Version 2 (NHP) [68] | 30 |
Pain Disability Index (PDI) [69] | 7 |
Profile of Mood States (POMS) [70] | 65 |
Revised Oswestry Pain Questionnaire (OPQ) [71] | 10 |
Rheumatoid Arthritis Quality of Life (RAQoL) [72] | 30 |
Rotterdam Symptom Checklist (RSC) [73] | 39 |
Sickness Impact Profile (SIP) [74] | 136 |
Stanford Health Assessment Questionnaire (modified) (HAQ) [50] | 20 |
WOMAC Osteoarthritis Index (WOMAC) [51] | 24 |
Zung Self-Rating Depression Scale (SDS) [75] | 20 |
Initial item reduction
Pre-testing and final revisions
Item calibration study
Data analysis
Dimensionality
IRT model
Item fit
Differential item functioning
Item and test information
Results
Study sample
Community sample with arthritis (N = 217) n (%) | Rheumatology clinic (N = 331) n (%) | Joint replacement waiting list (N = 340) n (%) | |
---|---|---|---|
Age
| |||
0–24 | 0 (0.0) | 5 (1.5) | 4 (1.2) |
25–44 | 23 (10.6) | 71 (21.5) | 28 (8.2) |
45–64 | 83 (38.2) | 160 (48.3) | 133 (39.1) |
65+ | 108 (49.8) | 84 (25.4) | 166 (48.8) |
Missing | 3 (1.4) | 11 (3.3) | 9 (2.7) |
Sex
| |||
Males | 69 (31.8) | 69 (20.9) | 150 (44.1) |
Females | 147 (67.7) | 250 (75.5) | 179 (52.7) |
Missing | 1 (0.5) | 12 (3.6) | 11 (3.2) |
Education
| |||
Less than high school | 50 (23.0) | 61 (18.4) | 81 (23.8) |
High school completed | 94 (43.3) | 146 (44.1) | 133 (39.1) |
Trade school/college/university | 72 (33.2) | 113 (34.1) | 115 (33.8) |
Missing | 1 (0.5) | 11 (3.3) | 11 (3.2) |
Self-reported co-morbidity
1
| |||
Back pain | 101 (46.5) | 106 (32.0) | 135 (39.7) |
Heart disease | 33 (15.2) | 30 (9.1) | 38 (11.2) |
Lung disease | 10 (4.6) | 35 (10.6) | 5 (1.5) |
Diabetes | 15 (6.9) | 26 (7.9) | 17 (5.0) |
Depression | 20 (9.2) | 36 (10.9) | 30 (8.8) |
Other2
| 147 (67.7) | 237 (71.6) | 227 (66.8) |
Self-rated health
| |||
Excellent | 8 (3.7) | 5 (1.5) | 26 (7.7) |
Very good | 57 (26.3) | 40 (12.1) | 98 (28.8) |
Good | 87 (40.1) | 103 (31.1) | 126 (37.1) |
Fair | 52 (24.0) | 135 (40.8) | 77 (22.7) |
Poor | 12 (5.5) | 46 (13.9) | 12 (3.5) |
Missing | 1 (0.5) | 2 (0.6) | 1 (0.3) |
Dimensionality
Item number | Daily Activities | Walking | Handling Objects | Pain or Discomfort | Feelings | |||||
---|---|---|---|---|---|---|---|---|---|---|
Loading | RMS | Loading | RMS | Loading | RMS | Loading | RMS | Loading | RMS | |
1 | 0.894 | 0.038 | 0.900 | 0.049 | 0.823 | 0.069 | 0.854 | 0.084 | 0.837 | 0.055 |
2 | 0.864 | 0.052 | 0.890 | 0.047 | 0.832 | 0.080 | 0.864 | 0.073 | 0.849 | 0.052 |
3 | 0.913 | 0.052 | 0.841 | 0.038 | 0.855 | 0.076 | 0.888 | 0.046 | 0.840 | 0.063 |
4 | 0.842 | 0.063 | 0.904 | 0.038 | 0.867 | 0.057 | 0.885 | 0.051 | 0.841 | 0.062 |
5 | 0.911 | 0.037 | 0.917 | 0.029 | 0.819 | 0.065 | 0.791 | 0.091 | 0.761 | 0.063 |
6 | 0.888 | 0.028 | 0.931 | 0.037 | 0.848 | 0.047 | 0.853 | 0.065 | 0.711 | 0.083 |
7 | 0.752 | 0.097 | 0.877 | 0.063 | 0.891 | 0.063 | 0.844 | 0.068 | 0.778 | 0.078 |
8 | 0.869 | 0.075 | 0.922 | 0.063 | 0.830 | 0.087 | 0.461 | 0.098 | 0.740 | 0.075 |
9 | 0.903 | 0.055 | 0.913 | 0.036 | 0.863 | 0.051 | 0.765 | 0.055 | 0.770 | 0.087 |
10 | 0.771 | 0.076 | 0.881 | 0.042 | 0.890 | 0.036 | 0.867 | 0.044 | 0.788 | 0.086 |
11 | 0.857 | 0.064 | 0.919 | 0.043 | 0.905 | 0.062 | 0.768 | 0.102 | 0.807 | 0.073 |
12 | 0.842 | 0.074 | 0.934 | 0.039 | 0.773 | 0.125 | 0.826 | 0.091 | 0.851 | 0.061 |
13 | 0.910 | 0.059 | 0.747 | 0.095 | 0.904 | 0.026 | 0.748 | 0.083 | 0.704 | 0.101 |
14 | 0.868 | 0.072 | 0.909 | 0.048 | 0.906 | 0.043 | 0.834 | 0.047 | 0.700 | 0.090 |
15 | 0.810 | 0.058 | 0.894 | 0.041 | 0.870 | 0.056 | 0.742 | 0.131 | 0.541 | 0.088 |
16 | 0.772 | 0.091 | 0.877 | 0.052 | 0.889 | 0.052 | 0.691 | 0.150 | 0.740 | 0.102 |
17 | 0.875 | 0.049 | 0.898 | 0.034 | 0.767 | 0.071 | 0.791 | 0.087 | 0.687 | 0.116 |
18 | 0.897 | 0.038 | 0.886 | 0.049 | 0.883 | 0.062 | 0.736 | 0.126 | 0.768 | 0.082 |
19 | 0.891 | 0.036 | 0.842 | 0.061 | 0.887 | 0.044 | 0.703 | 0.094 | 0.824 | 0.057 |
20 | 0.881 | 0.062 | 0.848 | 0.076 | 0.759 | 0.132 | 0.760 | 0.099 | 0.804 | 0.079 |
21 | 0.748 | 0.059 | 0.907 | 0.076 | 0.890 | 0.047 | 0.863 | 0.041 | 0.890 | 0.039 |
22 | 0.892 | 0.061 | 0.694 | 0.067 | 0.629 | 0.125 | 0.765 | 0.103 | 0.705 | 0.063 |
23 | 0.875 | 0.056 | 0.434 | 0.093 | 0.891 | 0.044 | 0.848 | 0.059 | 0.756 | 0.076 |
24 | 0.875 | 0.064 | 0.845 | 0.097 | 0.863 | 0.054 | 0.823 | 0.070 | 0.839 | 0.042 |
25 | 0.801 | 0.058 | 0.672 | 0.101 | 0.718 | 0.135 | 0.808 | 0.076 | 0.673 | 0.065 |
26 | 0.888 | 0.064 | 0.835 | 0.060 | 0.862 | 0.053 | 0.550 | 0.087 | 0.616 | 0.129 |
27 | 0.777 | 0.095 | 0.926 | 0.046 | 0.849 | 0.078 | 0.668 | 0.116 | 0.707 | 0.083 |
28 | 0.870 | 0.066 | 0.707 | 0.092 | 0.854 | 0.066 | 0.877 | 0.040 | 0.653 | 0.127 |
29 | 0.848 | 0.068 | 0.790 | 0.076 | 0.662 | 0.112 | 0.721 | 0.083 | 0.707 | 0.060 |
30 | 0.860 | 0.076 | 0.755 | 0.114 | 0.762 | 0.134 | 0.853 | 0.074 | 0.750 | 0.072 |
31 | 0.785 | 0.098 | 0.893 | 0.034 | 0.865 | 0.061 | 0.813 | 0.056 | 0.684 | 0.082 |
32 | 0.772 | 0.106 | 0.898 | 0.023 | 0.898 | 0.046 | 0.741 | 0.099 | 0.787 | 0.078 |
33 | 0.818 | 0.109 | 0.865 | 0.093 | 0.881 | 0.045 | 0.713 | 0.091 | 0.787 | 0.093 |
34 | 0.775 | 0.113 | 0.923 | 0.041 | 0.762 | 0.093 | 0.891 | 0.054 | 0.656 | 0.112 |
35 | 0.795 | 0.112 | 0.724 | 0.064 | 0.901 | 0.035 | 0.885 | 0.064 | 0.895 | 0.040 |
36 | 0.806 | 0.064 | 0.739 | 0.107 | 0.870 | 0.052 | 0.691 | 0.117 | 0.710 | 0.085 |
37 | 0.865 | 0.060 | 0.853 | 0.056 | 0.867 | 0.051 | 0.753 | 0.066 | 0.766 | 0.081 |
38 | 0.815 | 0.046 | 0.898 | 0.033 | 0.873 | 0.059 | 0.807 | 0.063 | 0.814 | 0.073 |
39 | 0.853 | 0.073 | 0.772 | 0.081 | 0.832 | 0.084 | 0.853 | 0.070 | ||
40 | 0.841 | 0.073 | 0.630 | 0.129 | 0.719 | 0.108 | ||||
41 | 0.840 | 0.069 | 0.836 | 0.067 | 0.785 | 0.108 | ||||
41 | 0.839 | 0.064 | 0.592 | 0.125 | 0.757 | 0.049 | ||||
43 | 0.804 | 0.097 | 0.913 | 0.047 | 0.780 | 0.099 | ||||
44 | 0.801 | 0.107 | 0.818 | 0.070 | ||||||
45 | 0.836 | 0.044 | 0.755 | 0.099 | ||||||
46 | 0.858 | 0.049 | ||||||||
47 | 0.871 | 0.049 | ||||||||
48 | 0.824 | 0.067 | ||||||||
49 | 0.754 | 0.111 | ||||||||
50 | 0.748 | 0.121 | ||||||||
51 | 0.809 | 0.066 | ||||||||
52 | 0.889 | 0.032 | ||||||||
53 | 0.854 | 0.061 | ||||||||
54 | 0.842 | 0.045 |
Item fit
Item Number | Item content | Lack of fit | DIF for sex | DIF for age |
---|---|---|---|---|
Daily Activities
| ||||
27 | Need for help with grooming | X | ||
40 | Difficulty traveling around the town or city | X | ||
41 | Difficulty traveling between cities | X | ||
42 | Difficulty traveling overseas | X | ||
Walking
| ||||
3 | Limitations in walking or climbing stairs | X | ||
4 | Usual ability to walk | X | ||
23 | Difficulty moving toes | X | ||
28 | Difficulty lifting one foot off the ground | X | ||
30 | Difficulty getting in and out of bed | X | ||
35 | Difficulty standing on toes | X | ||
38 | Description of ability to walk | X | ||
Handling Objects
| ||||
5 | Difficulty scratching the lower back | X | ||
22 | Difficulty putting on shoes, socks, or stockings | X | ||
24 | Difficulty cutting fingernails | X | ||
29 | Difficulty cutting toenails | X | ||
34 | Difficulty making bed | X | ||
37 | Difficulty putting a hand in a pocket | X | ||
38 | Difficulty wiping mouth with a napkin | X | ||
40 | Difficulty picking up clothing from the floor | X | ||
49 | Difficulty lifting and moving light furniture | X | ||
Pain or Discomfort
| ||||
8 | Time free from any physical complaints | X | ||
19 | Feeling perfectly healthy | X | ||
26 | Having minor pains and aches | X | ||
Feelings
| ||||
8 | Feeling tense or "high strung" | X | ||
15 | Losing temper | X | ||
19 | Feeling calm and peaceful | X | ||
29 | Worrying about the future | X | ||
31 | Having crying spells | X | ||
41 | Planning to commit suicide* | |||
44 | Feeling totally relaxed and free of tension | X | ||
45 | Feeling carefree | X |
Differential item functioning
Properties of final items
Item No. | Daily Activities | Walking | Handling Objects | Pain or Discomfort | Feelings |
---|---|---|---|---|---|
1 | 0.471 | 0.500 | 0.063 | 0.708 | 0.029 |
2 | 0.884 | 0.036 | 0.046 | 0.744 | 0.850 |
3 | 0.864 | - | 0.201 | 0.964 | 0.976 |
4 | 0.398 | - | 0.155 | 0.023 | 0.916 |
5 | 0.141 | 0.988 | - | 0.082 | 0.034 |
6 | 0.011 | 0.832 | 0.889 | 0.096 | 0.045 |
7 | 0.698 | 0.962 | 0.945 | 0.888 | 0.022 |
8 | 0.295 | 0.870 | 0.023 | - | - |
9 | 0.018 | 0.945 | 0.405 | 0.145 | 0.073 |
10 | 0.197 | 0.579 | 0.646 | 0.806 | 0.997 |
11 | 0.986 | 0.336 | 1.000 | 0.521 | 0.023 |
12 | 0.776 | 0.990 | 0.017 | 0.512 | 0.610 |
13 | 0.998 | 0.549 | 0.146 | 0.235 | 0.415 |
14 | 0.202 | 0.985 | 0.775 | 0.806 | 0.626 |
15 | 0.713 | 0.125 | 0.253 | 0.190 | - |
16 | 0.566 | 0.831 | 1.000 | 1.000 | 0.397 |
17 | 0.549 | 0.560 | 0.125 | 0.111 | 0.465 |
18 | 0.534 | 0.447 | 0.582 | 0.995 | 0.120 |
19 | 0.204 | 0.697 | 1.000 | - | - |
20 | 0.509 | 0.039 | 0.096 | 0.027 | 0.804 |
21 | 0.842 | 0.808 | 0.488 | 0.266 | 0.057 |
22 | 0.121 | 0.898 | - | 0.579 | 0.025 |
23 | 0.696 | - | 1.000 | 0.057 | 0.108 |
24 | 0.002* | 0.458 | - | 0.353 | 0.989 |
25 | 0.513 | 0.045 | 0.011 | 0.005* | 0.330 |
26 | 0.001* | 0.364 | 0.992 | - | 0.018 |
27 | - | 0.752 | 0.329 | 0.880 | 0.316 |
28 | 0.006* | - | 0.732 | 0.310 | 0.420 |
29 | 0.366 | 0.100 | - | 0.145 | - |
30 | 0.723 | - | 0.009* | 0.377 | 0.244 |
31 | 0.741 | 0.234 | 0.513 | 0.115 | - |
32 | 0.977 | 0.330 | 0.152 | 0.097 | 0.044 |
33 | 0.010 | 0.999 | 0.239 | 0.259 | 0.890 |
34 | 0.207 | 0.511 | - | 0.058 | 0.663 |
35 | 0.997 | - | 0.275 | 0.356 | 0.676 |
36 | 0.140 | 0.658 | 0.887 | 0.731 | 0.331 |
37 | 0.751 | 0.198 | - | 0.021 | 0.211 |
38 | 0.466 | - | - | 0.887 | 0.061 |
39 | 0.689 | 0.680 | 0.070 | 1.000 | |
40 | - | - | 0.976 | ||
41 | - | 0.414 | - | ||
42 | - | 0.054 | 0.002* | ||
43 | 0.040 | 1.000 | 0.119 | ||
44 | 0.233 | - | |||
45 | 0.494 | - | |||
46 | 0.246 | ||||
47 | 0.068 | ||||
48 | 0.938 | ||||
49 | - | ||||
50 | 0.173 | ||||
51 | 0.479 | ||||
52 | 0.995 | ||||
53 | 0.846 | ||||
54 | 0.988 |
Statistic | Daily Activities | Walking | Handling Objects | Pain or Discomfort | Feelings | |||||
---|---|---|---|---|---|---|---|---|---|---|
Location | Slope | Location | Slope | Location | Slope | Location | Slope | Location | Slope | |
Mean | -0.664 | 1.610 | -0.097 | 1.729 | -0.774 | 1.354 | -0.497 | 1.294 | -0.573 | 1.154 |
SD | 0.805 | 0.463 | 0.859 | 0.550 | 0.897 | 0.409 | 0.834 | 0.544 | 0.819 | 0.390 |
Min. | -2.237 | 0.970 | -1.274 | 0.611 | -1.698 | 0.662 | -1.896 | 0.649 | -2.349 | 0.560 |
25% | -1.434 | 1.264 | -0.708 | 1.346 | -1.341 | 1.036 | -1.169 | 0.859 | -1.186 | 0.863 |
Median | -0.511 | 1.466 | -0.380 | 1.747 | -1.180 | 1.278 | -0.352 | 1.102 | -0.639 | 1.071 |
75% | 0.014 | 1.947 | 0.456 | 2.145 | -0.451 | 1.707 | 0.071 | 1.627 | 0.211 | 1.434 |
Max. | 0.546 | 3.156 | 1.958 | 2.695 | 2.272 | 2.104 | 1.637 | 2.546 | 1.011 | 1.989 |