Table 1 Methodological characteristics of four cross-sectional surveys
From: Parental compliance - an emerging problem in Liverpool community child health surveys 1991-2006
Characteristics | 1991 | 1993 | 1998 | 2006 |
|---|---|---|---|---|
Number of schools | 15 | 15 | 10â•« | 15 |
Pre-notification by letter | Yes | Yes | Yes | Yes |
Sampling | Every second child | All children | All children | All children |
Re-visits for absenteeism | at 2-4 weeks | at 2-4 weeks | at 2 weeks | at 2 weeks |
Inclusion/Exclusion | none | none | none | none |
Months of survey | September to December | September to December | September to December | September to December |
Age of children | 5-11 years | 5-11 years | 5-11 years | 5-11 years |
Total number of questionnaires | 1872 | 3746 | 1964 | 1074 |
Mother completed questionnaire | 78.5 (1872) | 82.8 (3746) | 82.0 (1964) | 78.0 (1074) |
Father completed questionnaire | 4.8 (1872) | 6.0 (3746) | 5.6 (1964) | 4.3 (1074) |
Both parents completed questionnaire | 15.8 (1872) | 10.0 (3746) | 6.5 (1964) | 5.4 (1074) |
Questionnaire compliance,%*** | 92.0% (1872/2035) | 87.4 (3746/4288) | 78.1 (1964/2514) | 30.3 (1074/3540) |
Child’s weight | Yes | Yes | Yes | Yes |
Child’s height | Yes | Yes | Yes | Yes |
Questionnaire length | Reference | unchanged | New questions added* | New questions added** |
Incentives | None | None | None | None |