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Table 5 Overview of source data from three studies and harmonisation process for derivation of ICAD_SchoolTravel3

From: Harmonising data on the correlates of physical activity and sedentary behaviour in young people: Methods and lessons learnt from the international Children’s Accelerometry database (ICAD)

Source data

Harmonisation

Study

Wave

Variable(s): name(s), description

Summary

Category

Processing

Summary

SPEEDY*

Wave: 1

Variable names:

W1_a2acthrs_clean

W1_a2actmins_clean

W1_a3acthrs_clean

W1_a3actmins_clean

Duration of journey when walking or cycling to school

Continuous variables.

Duration when walking in minutes per day

Mean: 12.7

Median: 10

25th percentile: 5

75th percentile: 15

Range: 0, 60

Duration when cycling in minutes per day

Mean: 11.2

Median: 10

25th percentile: 5

75th percentile: 15

Range: 0, 60

Less than 5 min

If duration of walking or cycling <=5

n = 356

6–15 min

If duration of walking or cycling = 6–15 (inclusive)

n = 432

More than 15 min

If duration of walking or cycling >15

n = 193

Missing

 

n = 1083

KISS

Wave: 1

Variable name: a_schulweg_hin_sommer_time

Duration of journey to school

Continuous variable.

Duration in minutes per day:

Mean: 9.9

Median: 10

25th percentile: 5

75th percentile: 15

Range: 1, 30

Missing, n = 88

Less than 5 min

If [a_schulweg_hin_sommer_time] < =5

n = 153

6–15 min

If [a_schulweg_hin_sommer_time] = 6–15 (inclusive)

n = 249

More than 15 min

If [a_schulweg_hin_sommer_time] >15

n = 50

Missing

If [a_schulweg_hin_sommer_time] = Missing

n = 88

Ballabeina

Wave: 1

Variable name:

W1_a_langeweg

Duration of journey to school

Categorical variable:

<10 min, n = 514

10–20 min, n = 82

>20 min, n = 10

Missing, n = 63

Response categories for this study captured different duration boundaries to those of the harmonised variable and could not be suitably collapsed or otherwise matched. Therefore, this study was not included in the harmonised variable.

  1. For brevity, processing is summarised for data collected at study wave 1 only. Similar procedures were used for subsequent waves. *The SPEEDY questionnaire did not allow for separate estimation of journey duration amongst those who travelled by bus/train or car to school. Therefore, only participants who indicated walk or cycle as their mode of travel were included in his variable