GCSE results returns
The figures shown in the table below are numbers of families (twin pairs). The GCSE study has finished for all cohorts, and all data are incorporated into the dataset.
| School cohort | 1 | 2 | 3 | 4 | TOTAL |
|---|---|---|---|---|---|
| Twin birth dates | Jan-94 to Aug-94 | Sep-94 to Aug-95 | Sep-95 to Aug-96 | Sep-96 to Dec-96 | |
| Original TEDS sample | 3265 | 4888 | 4268 | 1524 | 13945 |
| Results forms sent | 2318 | 3802 | 3319 | 1174 | 10613 |
| Results returned (both completed) | 1582 | 2049 | 2249 | 804 | 6684 |
| Percentage of families returning full results | 68.2% | 53.9% | 67.8% | 68.5% | 63.0% |
| Partial returns (only one completed) | 40 | 34 | 47 | 18 | 139 |
| GCSE data in the dataset (complete pairs) | 1557 | 2047 | 2242 | 794 | 6640 |
Web Study returns
The figures shown are numbers of families (twin pairs). Note that the web study only involved families in school cohorts 1 and 2.
| School cohort | 1 | 2 | TOTAL |
|---|---|---|---|
| Twin birth dates | Jan-94 to Aug-94 | Sep-94 to Aug-95 | |
| Original TEDS sample | 3265 | 4888 | 8153 |
| Families sent web login details | 2382 | 3899 | 6281 |
| Parent consent and SES qnrs completed | 1339 | 1940 | 3279 |
| Percentage of contacted families giving on line consent | 56.2% | 49.8% | 52.2% |
| All 16 web activities completed (both twins) | 839 | 1375 | 2214 |
| Some twin web activities completed (but both twins did not finish) | 457 | 509 | 966 |
| Percentage of contacted families with ALL web tests completed | 35.2% | 35.3% | 35.2% |
| Percentage of contacted families with ANY twin web data (partial or complete) | 54.4% | 48.3% | 50.6% |
| Parent SES web data in the dataset | 1339 | 1940 | 3279 |
| Paired twin web data (at least one test completed) in the dataset | 1024 | 1590 | 2614 |
| Unpaired twin web data (at least one test completed) in the dataset | 259 | 275 | 534 |
Behaviour/LEAP Study booklet returns
The figures shown are numbers of families (twin pairs). The Behaviour/LEAP study has finished for all cohorts, and all data are incorporated into the dataset.
| School cohort | 1 | 2 | 3 & 4 | TOTAL |
|---|---|---|---|---|
| Twin birth dates | Jan-94 to Aug-94 | Sep-94 to Aug-95 | Sep-95 to Dec-96 | |
| Original TEDS sample | 3265 | 4888 | 5792 | 13945 |
| Families sent Behaviour/LEAP booklets | 2340 | 3864 | 4670 | 10874 |
| All three booklets completed and returned | 1117 | 1581 | 2360 | 5058 |
| Percentage of contacted families with all three booklets returned | 47.7% | 40.9% | 50.5% | 46.5% |
| One or two booklets completed and returned | 34 | 44 | 27 | 105 |
| Parent booklet data in the dataset | 1142 | 1612 | 2374 | 5128 |
| Paired twin booklet data in the dataset | 1121 | 1588 | 2365 | 5074 |
| Unpaired twin booklet data in the dataset | 20 | 29 | 18 | 67 |
LEAP-2 Study booklet returns
The figures shown are numbers of families (twin pairs). The LEAP-2 study has finished for all cohorts, and all data are incorporated into the dataset.
| School cohort | 1 | 2 | 3 & 4 | TOTAL |
|---|---|---|---|---|
| Twin birth dates | Jan-94 to Aug-94 | Sep-94 to Aug-95 | Sep-95 to Dec-96 | |
| Original TEDS sample | 3265 | 4888 | 5792 | 13945 |
| Families sent LEAP-2 booklets | 426 | 543 | 804 | 1773 |
| All three booklets completed and returned | 334 | 461 | 676 | 1471 |
| Percentage of contacted families with all three booklets returned | 78.4% | 84.9% | 84.1% | 83.0% |
| One or two booklets completed and returned | 8 | 6 | 3 | 17 |
| Parent booklet data in the dataset | 341 | 462 | 672 | 1475 |
| Paired twin booklet data in the dataset | 331 | 461 | 673 | 1465 |
| Unpaired twin booklet data in the dataset | 10 | 5 | 5 | 20 |