Introduction 1 2 2 7 3 8 9 10 11 14 15 17 18 20 21 22 23 26 In this study, we compared indicators of the feasibility, reliability, and validity of the CHQ-CF in a subgroup of adolescents who completed the standard paper version of the CHQ-CF with the same indicators in another subgroup of adolescents who completed a newly developed internet version of the questionnaire. Additionally, we compared the mean CHQ-CF scores and distributions of the scale scores between both subgroups. A randomized parallel group design was applied in a large adolescent population (13–7  years old), ensuring that both subgroups were comparable. the number of missing answers (indicator of feasibility), the distribution of the scale scores including mean scale scores in the whole sample and in gender and age specific subgroups, the internal consistency reliability of multi-item scales (indicator of reliability), the ability of the CHQ-CF to discriminate between subgroups with and without self-reported chronic conditions (indicator of construct validity). Methods Study population In 2003, 1,071  students in 55  classes of various educational levels in the 3rd year of seven secondary schools (13–7 years old) in the area of Vlaardingen (metropolitan area) and Harderwijk (rural area), The Netherlands, were invited to complete the Child Health Questionnaire Child Form (CHQ-CF). The parents and students each received written information about the study several weeks before data collection; parents could refuse their child’s participation, and participation by the students was voluntary. Data collection 1 3 3 3 27 Table 1 a CHQ-CF Scales Number of items Description low score Description high score Physical functioning (PF) 9 Child is greatly limited in performing all physical activities, including self-care, due to health Child performs all types of physical activities, including the most vigorous without limitations due to health b 3 Child is greatly limited in school work or activities with friends as a result of emotional problems Child has no limitations in schoolwork or activities with friends as a result of emotional problem b 3 Child is greatly limited in school work or activities with friends as a result of behavior problems Child has no limitations in schoolwork or activities with friends as a result of behavior problems Role functioning: Physical (RP) 3 Child is greatly limited in school work or activities with friends as a result of physical health Child has no limitations in schoolwork or activities with friends as a result of physical health Bodily pain (BP) 2 Child has extremely severe, frequent and limiting bodily pain Child has no pain or limitations due to pain General behavior (BE) 17 Child very often exhibits aggressive, immature, delinquent behavior Child never exhibits aggressive, immature, delinquent behavior Mental health (MH) 16 Child has feelings of anxiety and depression all of the time Child feels peaceful, happy, and calm all of the time Self esteem (SE) 14 Child is very dissatisfied with abilities, looks, family/peer relationships and life overall Child is very satisfied with looks, family/peer relationships and life abilities, overall General health perceptions (GH) 12 Child believes his/her health is poor and likely to get worse Child believes his/her health is excellent and will continue to be so c 1 Child’s health is much worse now than 1  year ago Child’s health is much better now than 1  year ago Family activities (FA) 6 The child’s health very often limits and interrupts family activities or is a source of family tension. The child’s health never limits or interrupts family activities nor is family a source of tension Family cohesion (FC) 1 Family’s ability to get along is rated “poor– Family’s ability to get along is rated “excellent– a 3 b c Randomization Within each school class, students were randomly assigned to either the paper or the internet mode of administration using SPSS-generated random numbers. Students completed the questionnaires, either on paper or online in a classroom with computers linked to the internet, under the supervision of a research assistant; the students were allowed adequate privacy. Analysis t 2 U U n n n n d n a a 2 n b b 2 n a n b 28 d d d 28 d 29 30 31 r r z 32 r 33 d 28 All analyses were done using SPSS, Version 11.0.1. The medical ethical committee of the Erasmus MC-University Medical Center Rotterdam, approved the study. Results Participants and randomization 2 2 P 2 34 Table 2 n n n  n n n P Mean (SD) or Range n % of Participants Mean (SD) or Range n % of Participants Mean (SD) or Range n % of Participants Internet versus paper mode Demographic characteristics           Age (years)           Mean (SD) 14.7 (0.68)   14.7 (0.68)   14.7 (0.68)   a Range 13–7   13–7   13–7    Gender           Women  501 54%  244 51%  257 56% b Born in the Netherlands           Yes  866 93%  441 93%  425 93% b Educational level of the school           Lower secondary education  545 58%  274 58%  271 59%  Intermediate secondary education  179 19%  94 20%  85 19% c Higher secondary education  209 22%  107 23%  102 22%  Chronic conditions:           Asthma           Yes  76 8%  40 8%  36 8% b Allergies           Yes  229 25% 118 25%   111 24% b Problems with hearing           Yes  62 7% 30 6%   32 7% b Problems with seeing           Yes  78 8% 39 8%   39 9% b Headaches or migraine           Yes  159 17% 81 17%   78 17% b Chronic low back pain           Yes  159 17% 88 19%   71 16% b Depression and/or anxiety attacks           Yes  74 8% 36 8%   38 8% b a t b df c df Difference in the number of missing answers between different modes of CHQ-CF administration P CHQ-CF scores by mode of administration 3 P d 3 P P P P P P d Table 3 n n a Mode of admini stration Mean (SD) Paper versus internet mode of administration Range of scores d e th th th Cronbach’s alpha f Average item-other scale correlation P b d c Physical Functioning Paper 96.0 (6.9) 0.37 0.01 44–00 56 0 96 100 100 0.69 0.40 0.19  Internet 95.8 (7.2)   37–00 53 0 93 100 100 0.72 0.44 0.18 Role funct.-Emo/beh Paper 89.4 (17.2) 0.14 0.00 0–00 60 0 78 100 100 0.81 0.65 0.35  Internet 89.5 (15.1)   0–00 54 0 86 100 100 g g 0.28 Role funct.-Physical Paper 95.0 (12.9) 0.02 0.05 22–00 81 0 100 100 100 0.86 0.74 0.30  Internet 94.4 (11.7)   22–00 75 0 89 100 100  g  g 0.25 Bodily Pain Paper 73.5 (22.7) 0.56 –0.05 0–00 25 0 60 80 100 0.88 0.80 0.35  Internet 74.7 (21.4)   0–00 24 1 60 80 90 0.89 0.81 0.30 General Behavior Paper 80.9 (10.6) 0.00 0.21 25–00 1 0 75 82 88 0.83 0.44 0.26  Internet 78.6 (11.4)   35–00 0 0 72 79 87 0.85 0.46 0.26 Mental Health Paper 76.5 (15.4) 0.01 0.12 14–00 2 0 69 80 89 0.92 0.63 0.35  Internet 74.6 (14.8)   14–00 0 0 67 77 84 h 0.60 0.31 Self Esteem Paper 74.7 (12.2) 0.99 0.02 20–00 1 0 68 75 82 0.88 0.56 0.30  Internet 74.4 (11.6)   25–00 0 0 70 76 82 0.87 0.55 0.28 General Health Paper 73.5 (16.5) 0.59 0.05 19–00 3 0 63 76 86 0.82 0.50 0.28  Internet 72.6 (16.7)   20–00 1 0 63 75 86 0.81 0.58 0.28 Family Activities Paper 80.0 (17.7) 0.03 0.11 8–00 17 0 67 83 96 0.81 0.58 0.24  Internet 78.1 (16.9)   25–00 13 0 67 79 92 0.78 0.54 0.24 Family Cohesion Paper 70.6 (23.5) 0.91 0.00 0–00 18 2 60 85 85 na na 0.36  Internet 70.7 (23.0)   0–00 16 2 60 85 85 na na 0.33 a b c 28 29 d/e f g h g P h P 31 33 na Not applicable; Role funct.-Emo/beh - Role functioning-emotional behavioral; Role funct.-Physical - Role functioning-physical Internal consistency reliability of scales by mode of administration P P 3 P 3 Construct validity by mode of administration P 4 P 4 Table 4 n n   Number of chronic conditions per participant a Mode of admini- stration 0 conditions 1 or 2 conditions ≥ conditions 1 or 2 versus 0 conditions ≥ versus 0 conditions P  P P n n n  n  n  n d b  d b Physical functioning Paper 97 (5) 96 (7) 90 (10) 0.24 0.80*    Internet 97 (5) 95 (7) 89 (12) 0.28 0.64* 0.00 0.95 0.52 Role funct.-emo/behav Paper 93 (13) 88 (18) 77 (24) 0.25 0.64*    Internet 91 (14) 89 (15) 79 (18) 0.15 0.66* 0.00 0.20 0.72 Role funct.-physical Paper 97 (11) 94 (13) 91 (17) 0.19 0.34    Internet 96 (10) 94 (13) 91 (13) 0.14 0.34 0.00 0.07 0.69 Bodily pain Paper 82 (18) 70 (22) 47 (24) 0.52* 1.45*    Internet 80 (18) 72 (21) 55 (24) 0.39 1.03* 0.00 0.20 0.32 General behavior Paper 84 (9) 80 (10) 71 (13) 0.40 0.98*    Internet 81 (10) 78 (11) 69 (14) 0.26 0.90* 0.00 0.03 0.65 Mental health Paper 83 (10) 74 (16) 57 (16) 0.56* 1.58*    Internet 80 (11) 72 (15) 59 (18) 0.50 1.20* 0.00 0.26 0.29 Self esteem Paper 79 (10) 73 (12) 61 (12) 0.52* 1.44*    Internet 77 (9) 73 (12) 66 (14) 0.33 0.80* 0.00 0.26 0.06 General health Paper 80 (14) 71 (15) 54 (14) 0.57* 1.82*    Internet 79 (13) 70 (17) 55 (18) 0.54* 1.29* 0.00 0.74 0.58 Family activities Paper 83 (16) 79 (18) 70 (20) 0.26 0.67*    Internet 81 (16) 78 (17) 66 (15) 0.17 0.97* 0.00 0.03 0.51 Family cohesion Paper 77 (21) 68 (23) 53 (26) 0.38 0.89*    Internet 74 (20) 68 (24) 64 (28) 0.24 0.38 0.00 0.18 0.05 a b d 28 29 Role funct.-Emo/beh - Role functioning-emotional behavioral; Role funct.-Physical - Role functioning-physical Discussion and conclusions In this study we applied a randomized design to compare the results of the Child Health Questionnaire-Child Form (CHQ-CF) administered by a paper questionnaire and by an online questionnaire. The results provided support for the feasibility, internal consistency reliability, and construct validity of the CHQ-CF scales. Both modes of questionnaire administration yielded comparable scale scores and showed comparable psychometric properties. Additionally, the study provided reference/norm scores for clinical studies (general population of 13–7 year olds). Strengths of the current study 34 Limitations 25 35 7 35 In this study, internet and paper questionnaires were completed in a controlled environment with adequate privacy and supervision. This may not be the case during future applications. We are unaware of the impact less privacy during completion of the questionnaires may have, but this would apply to both the paper and the internet versions of the questionnaire. 2 3 Psychometric properties The psychometric properties, with only a few exceptions, were equal between the two modes of questionnaire administration. The Cronbach’s α of the scale “physical functioning–in the subgroup administered the paper version of the questionnaire was just under 0.70, and the difference with the alpha in the subgroup administered the internet version was not statistically significant. Missing values n n P Score differences between modes of questionnaire administration 23 24 25 25 26 36 36 d d 28 d 29 Conclusions With increasing application of online health questionnaires rather than questionnaires on paper, especially in adolescent populations, it should be noted that comparison of results requires that the scores between these modes of administration do not show meaningful statistically significant differences. This study showed that, overall, paper and internet versions of the CHQ-CF yielded only a few, negligible or small, differences. Paper and internet modes of CHQ-CF administration may be combined in a single study, although researchers should consider the possibility of minor score differences depending on the mode of administration for some scales. We recommend repeated studies in other populations, including clinical populations, to confirm or reject our results.