Returns of Family Booklet and SLQ Data
The figures shown in the table below are numbers of families (twin pairs). Returns include both paper questionnaires and on line questionnaires.
| 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 |
| Booklet pack sent | 2487 | 3946 | 4685 | 11118 |
| Booklets returned (all three completed) | 1132 | 1205 | 712 | 3049 |
| Percentage of families returning all three booklets | 45.5% | 30.5% | 15.2% | 27.4% |
| Partial returns (one or two booklets returned) | 25 | 138 | 523 | 686 |
| SLQ pack sent | 2488 | 3952 | 4496 | 10936 |
| SLQ returned | 1021 | 1100 | 1439 | 3560 |
| Percentage of SLQ questionnaires back | 41.0% | 27.8% | 32.0% | 32.6% |
| Parent booklet data in the dataset | 1146 | 1261 | 966 | 3373 |
| Paired twin booklet data in the dataset | 1131 | 1219 | 808 | 3158 |
| Unpaired twin booklet data in the dataset | 16 | 82 | 271 | 369 |
| SLQ data in the dataset | 1017 | 1098 | 1441 | 3556 |
Returns of Twin Web Data
The returns of data shown in the table below represent both returns and actual data in the analysis dataset. The figures shown are numbers of families (twin pairs).
| 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 web login details | 2487 | 3833 | 4685 | 11005 |
| On line consent form completed | 1298 | 1041 | 1733 | 4072 |
| Percentage of contacted families giving on line consent | 52.2% | 27.2% | 37.0% | 37.0% |
| All 3 web tests completed (both twins) | 1097 | 515 | 837 | 2449 |
| Some web tests completed (but both twins did not finish) | 184 | 457 | 727 | 1368 |
| Percentage of contacted families with ALL web tests completed | 44.1% | 13.4% | 17.9% | 22.3% |
| Percentage of contacted families with ANY twin web data (partial or complete) | 51.5% | 25.4% | 33.4% | 34.7% |
Returns of Twin Telephone (Language) and Teacher Data
These data were only collected in cohort 1. The figures shown in the table below are numbers of families (twin pairs).
| Attempted contact for language telephone tests | 649 |
|---|---|
| language tests completed (both twins) | 605 |
| Percentage of targetted families with language tests completed | 93.2% |
| Consents sent for teacher study | 2487 |
| Parents gave consent (written or verbal) to contact teachers | 1326 |
| Percentage of contacted families giving teacher consent | 53.3% |
| Teacher questionnaires sent (pairs) | 1323 |
| Teacher questionnaires returned for both twins | 703 |
| Teacher questionnaires returned for only one twin | 336 |
| Percentage of questionnaires sent that were returned: | 65.8% |
| Paired data in the dataset | 699 |
| Unpaired data in the dataset | 334 |