This page summarises data returns in the 3 Year booklet study.
Most of the figures in the table below are based on information logged in the TEDS admin database. However, figures for 'data in the dataset' are based on the final analysis dataset itself. Discrepancies between returns and actual data arise because of logging errors, unusable data, and losses of data.
Families contacted in this study were a subset of the TEDS sample, and did not include inactive families in the larger original ONS sample.
The figures shown in the table below are numbers of families (twin pairs). Note that families in the 1996 cohort were not contacted for this study.
| Cohort (birth year of twins): | 1994 | 1995 | TOTAL |
|---|---|---|---|
| TEDS sample | 4912 | 4901 | 9813 |
| 3 Year booklets sent | 4623 | 4626 | 9249 |
| 3 Year booklets returned | 3119 | 2997 | 6116 |
| Percentage of booklets returned | 67.5% | 64.8% | 66.1% |
| Data in the dataset | 3095 | 2964 | 6059 |