Table 3.
Agreement between questionnaires for the test–retest reliability study (n 111) and between questionnaires and interviews for the construct validity study (n 20), as indicated by intraclass correlation coefficient (ICC) or Cohen's kappa coefficient (κ) and percentage agreement (% Agree); DOiT (Dutch Obesity Intervention in Teenagers) questionnaire assessing energy balance-related behaviours. Results are presented per questionnaire item
| Reliability | Validity | |||
|---|---|---|---|---|
| Item | ICC/κ | % Agree | ICC/κ | % Agree |
| Consumption of soft drinks | ||||
| How many days a week do you drink soft drinks? (B1) | 0·59 | 51 | 0·34 | 60 |
| How many soft drinks do you drink on a school day? Cartons/small bottles (200 ml) (B2a) | 0·74 | 67 | 0·12 | 35 |
| How many soft drinks do you drink on a school day? Glasses (200 ml) (B2b) | 0·45 | 46 | 0·47 | 35 |
| How many soft drinks do you drink on a school day? Cans (330 ml) (B2c) | 0·61 | 61 | 0·24 | 70 |
| How many soft drinks do you drink on a school day? Bottles (500 ml) (B2d) | 0·28 | 81 | 0·17 | 75 |
| How many soft drinks do you drink on a weekend day? Cartons/small bottles (200 ml) (B3a) | 0·52 | 67 | 0·16 | 55 |
| How many soft drinks do you drink on a weekend day? Glasses (200 ml) (B3b) | 0·63 | 33 | 0·34 | 45 |
| How many soft drinks do you drink on a weekend day? Cans (330 ml) (B3c) | 0·63 | 67 | 0·39 | 70 |
| How many soft drinks do you drink on a weekend day? Bottles (500 ml) (B3d) | 0·62 | 76 | −0·04 | 55 |
| How many soft drinks did you drink yesterday? Cartons or small bottles (200 ml) (B4a) | 0·55 | 57 | 0·32 | 45 |
| How many soft drinks did you drink yesterday? Glasses (200 ml) (B4b) | 0·51 | 37 | 0·53 | 47 |
| How many soft drinks did you drink yesterday? Cans (330 ml) (B4c) | 0·57 | 75 | 0·53 | 80 |
| How many soft drinks did you drink yesterday? Bottles (500 ml) (B4d) | 0·58 | 77 | 0·46 | 60 |
| Consumption of fruit juices | ||||
| How many days a week do you drink fruit juices? (B5) | 0·75 | 42 | 0·41 | 25 |
| How many fruit juices do you drink on a school day? Cartons/small bottles (200 ml) (B6a) | 0·54 | 66 | 0·40 | 45 |
| How many fruit juices do you drink on a school day? Glasses (200 ml) (B6b) | 0·52 | 50 | 0·19 | 42 |
| How many fruit juices do you drink on a school day? Cans (330 ml) (B6c) | 0·36 | 90 | 0·00 | 84 |
| How many fruit juices do you drink on a school day? Bottles (500 ml) (B6d) | 0·45 | 79 | −0·06 | 74 |
| How many fruit juices do you drink on a weekend day? Cartons/small bottles (B7a) | 0·36 | 73 | −0·12 | 63 |
| How many fruit juices do you drink on a weekend day? Glasses (200 ml) (B7b) | 0·57 | 41 | 0·12 | 25 |
| How many fruit juices do you drink on a weekend day? Cans (330 ml) (B7c) | 0·36 | 88 | 0·00 | 83 |
| How many fruit juices do you drink on a weekend day? Bottles (500 ml) (B7d) | 0·40 | 79 | 0·00 | 79 |
| How many fruit juices did you drink yesterday? Cartons or small bottles (200 ml) (B8a) | 0·50 | 66 | 0·45 | 60 |
| How many fruit juices did you drink yesterday? Glasses (200 ml) (B8b) | 0·55 | 56 | 0·30 | 35 |
| How many fruit juices did you drink yesterday? Cans (330 ml) (B8c) | 0·57 | 94 | * | 100 |
| How many fruit juices did you drink yesterday? Bottles (500 ml) (B8d) | 0·41 | 86 | −0·08 | 84 |
| Consumption of sweets | ||||
| How many days a week do you eat sweets? (C1) | 0·66 | 48 | 0·60 | 30 |
| How many sweets do you eat on a school day? (C2) | 0·71 | 49 | 0·21 | 10 |
| How many sweets do you eat on a weekend day? (C3) | 0·73 | 37 | 0·07 | 15 |
| How many sweets did you eat yesterday? (C4) | 0·59 | 47 | 0·37 | 15 |
| What kind of sweets do you eat most? (C5) | 0·60 | 68 | 0·14 | 33 |
| Consumption of snacks | ||||
| How many days a week do you eat snacks? (C6) | 0·50 | 31 | −0·11 | 15 |
| How many small snacks (chips/peanuts) do you eat on a school day? (C7a) | 0·62 | 45 | 0·13 | 25 |
| How many big snacks (hamburger/French fries) do you eat on a school day? (C7b) | 0·58 | 59 | −0·08 | 68 |
| How many small snacks do you eat on a weekend day? (C8a) | 0·53 | 36 | 0·44 | 35 |
| How many big snacks do you eat on a weekend day? (C8b) | 0·64 | 56 | 0·08 | 42 |
| How many small snacks did you eat yesterday? (C9a) | 0·49 | 56 | 0·25 | 50 |
| How many big snacks did you eat yesterday? (C9b) | 0·46 | 68 | −0·07 | 78 |
| Breakfast/meals | ||||
| On how many days during the school week (Monday to Friday) do you eat breakfast? (D1) | 0·83 | 84 | 0·91 | 75 |
| On how many days in the weekend (Saturday and Sunday) do you eat breakfast? (D2) | 0·64 | 86 | 0·63 | 85 |
| What do you usually drink for breakfast? Nothing (D3a) | 0·37 | 94 | * | 95 |
| What do you usually drink for breakfast? Tea/coffee (D3b) | 0·72 | 88 | 0·67 | 85 |
| What do you usually drink for breakfast? Milk/yoghurt drink (D3c) | 0·71 | 86 | 0·69 | 85 |
| What do you usually drink for breakfast? Fruit juice (D3d) | 0·67 | 89 | 0·16 | 60 |
| What do you usually drink for breakfast? Liquid breakfast (D3e) | 0·65 | 96 | * | 100 |
| What do you usually drink for breakfast? Soft drink/energy drink (D3f) | 0·54 | 94 | 0·57 | 85 |
| What do you usually eat for breakfast? Nothing (D3g) | 0·82 | 98 | 0·62 | 90 |
| What do you usually eat for breakfast? Bread/crackers(D3h) | 0·66 | 86 | 0·12 | 60 |
| What do you usually eat for breakfast? Cereals (D3i) | 0·68 | 88 | 0·48 | 85 |
| What do you usually eat for breakfast? Croissant/coffee roll (D3j) | 0·51 | 88 | 0·00 | 65 |
| What do you usually eat for breakfast? Biscuit/sweet/snack (D3k) | * | 99 | * | 100 |
| Did you eat breakfast yesterday? (D4) | 0·77 | 93 | 1·00 | 100 |
| Did you eat lunch yesterday? (D5) | 0·37 | 86 | 0·44 | 90 |
| Did you eat dinner yesterday? (D6) | −0·02 | 95 | * | 100 |
| Screen behaviour | ||||
| How long do you watch television on a school day? (min/d) (including watching DVD) (E1a) | 0·66 | 44 | 0·52 | 35 |
| How long do you watch television on a weekend day? (including watching DVD) (E1b) | 0·65 | 35 | 0·52 | 15 |
| How long did you watch television yesterday? (E2) | 0·60 | 42 | 0·53 | 25 |
| How long do you spend behind the computer for playing games and leisure activities on a school day? (E3a) | 0·62 | 47 | 0·65 | 45 |
| How long do you spend behind the computer for playing games and leisure activities on a weekend day? (E3b) | 0·64 | 29 | 0·25 | 35 |
| How long did you spend behind the computer for playing games and leisure activities yesterday? (E4) | 0·43 | 30 | 0·73 | 35 |
| Active transport | ||||
| How many days a week do you walk to school? (F1) | 0·21 | 97 | * | 100 |
| If you walk to school, how long does it take you to walk to school? (F2) | 0·65 | 97 | * | 100 |
| How many days a week do you bike to school? (F3) | 0·78 | 94 | 1·00 | 100 |
| If you bike to school, how long does it take you to bike to school? (F4) | 0·91 | 64 | 0·68 | 45 |
| Did you go to school in other ways than walking or biking in the last 5 school days? No (F5a) | 0·32 | 88 | 0·46 | 90 |
| Did you go to school in other ways than walking or biking in the last 5 school days? Yes, … times by public transport (F5b) | 0·86 | 96 | 0·00 | 95 |
| Did you go to school in other ways than walking or biking in the last 5 school days? Yes, … times by car/scooter/moped (F5c) | 0·74 | 88 | 1·00 | 100 |
| How did you go to school yesterday? By bicycle (F6a) | 0·17 | 88 | 1·00 | 100 |
| How did you go to school yesterday? Walking (F6b) | −0·01 | 96 | 1·00 | 100 |
| How did you go to school yesterday? By public transport (F6c) | 0·32 | 96 | * | 100 |
| How did you go to school yesterday? By car/scooter/moped (F6d) | 0·19 | 94 | 1·00 | 100 |
| When you go somewhere else than school, how do you go there? By bicycle (F7a) | 0·21 | 87 | * | 95 |
| When you go somewhere else than school, how do you go there? Walking (F7b) | 0·47 | 84 | 0·03 | 65 |
| When you go somewhere else than school, how do you go there? By public transport (F7c) | 0·22 | 95 | * | 100 |
| When you go somewhere else than school, how do you go there? By car/scooter/moped (F7d) | 0·58 | 83 | 0·24 | 70 |
| Physical activity | ||||
| Do you participate in a sport at a sports club? (G1) | 0·98 | 99 | 0·86 | 95 |
| How many hours a week do you do this sport? (G3) | 0·94 | 73 | 0·78 | 53 |
| Do you participate in a second sport at a sports club? (G4) | 0·79 | 95 | 0·69 | 90 |
| How many hours a week do you do this second sport? (G6) | 0·76 | 87 | 0·96 | 90 |
| Do you participate in a third sport at a sports club? (G7) | * | 99 | * | 100 |
| How many hours a week do you do this third sport? (G9) | 0·00 | 99 | * | 100 |
| Do you participate in sports outside a sports club? (G10) | 0·64 | 84 | 0·33 | 69 |
| How many hours a week do you do these sports? (G11) | 0·64 | 47 | 0·45 | 28 |
| How long did you play sports yesterday? (at a sports club and outside a sports club) (G12) | 0·63 | 37 | −0·17 | 26 |
| How important do you think it is to participate in sports? (from very important to not important at all) (G13) | 0·75 | 85 | 0·07 | 45 |
| What do you usually do during physical activity lessons at school? (H1) | * | 96 | * | 85 |
| Which of the following statements fits the most to the things you do during recess? (H2) | 0·66 | 81 | * | 75 |
| How many hours do you do after-school-time physical activities at school? (H3) | 0·47 | 66 | −0·06 | 50 |
| Having a job | ||||
| Do you have an additional job at the moment? (I1) | 0·91 | 96 | 0·83 | 95 |
| I have a job – bringing around newspapers (I2a) | 0·96 | 99 | 1·00 | 100 |
| I have a job – stocking shelves at the supermarket (I2b) | 1·00 | 100 | * | 100 |
| I have a job – babysitting (I2c) | 0·93 | 99 | * | 95 |
| I have a job – cleaning (I2d) | 0·66 | 99 | * | 100 |
| I have a job – something else (I2e) | 1·00 | 100 | 1·00 | 100 |
| How many hours a week do you work? (I3) | 0·97 | 89 | 0·97 | 95 |
*Zero variance.