TEDS Data Dictionary

18 Year Data Returns

Contents of this page:

Introduction

This page summarises returns in the various parts of the 18 year study: the twin contact study, the twin questionnaire study, and the various web studies (Perception, FFMP, Bricks, Kings Challenge and Navigation). These studies were administered independently at different times, and often with different samples.

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 apparent returns and actual data arise because of logging errors, unusable data, and losses of data.

The main 18 Year Study page gives full details of how the data were collected.

Returns

The figures shown in the table below 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 Aug-96 Sep-96 to Dec-96
Original TEDS sample 3265 4888 4268 1524 13945
Twin Contact Study Twin contact forms sent 2365 3883 3376 1173 10797
Returned for both twins 1009 1477 1412 461 4359
Percentage of families returning both forms 42.7% 38.0% 41.8% 39.3% 40.4%
Partial returns (only one returned) 29 41 36 13 119
Questionnaire Study Twin questionnaires sent 2323 3827 3301 1137 10588
Returned for both twins 1029 2794 2446 799 7068
Percentage of families completed (both twins) 44.3% 73.0% 74.1% 70.3% 66.8%
Partial returns (only one returned) 66 68 42 21 197
Data in the dataset (complete pairs) 1023 2793 2434 798 7048
Perception Study Invitations sent 2282 100 - - 2382
Battery completed by both twins 913 42 - - 955
Percentage of families completed (both twins) 40.0% 42.0% - - 40.1%
Partial returns (one twin completed) 319 14 - - 333
Data in the dataset (complete pairs) 913 42 - - 955
Bricks Study Invitations sent 827 1357 - - 2184
Battery completed by both twins 467 799 - - 1266
Percentage of families completed (both twins) 56.5% 58.9% - - 58.0%
Partial returns (one twin completed) 168 267 - - 435
Data in the dataset (complete pairs) 467 799 - - 1266
Fashion Study Invitations sent - - 3166 - 3166
Battery completed by both twins - - 1305 - 1305
Percentage of families completed (both twins) - - 41.2% - 41.2%
Partial returns (one twin completed) - - 457 - 457
Data in the dataset (complete pairs) - - 1301 - 1301
Kings Challenge Study Invitations sent 1246 1796 - - 3042
Battery completed by both twins 397 617 - - 1014
Percentage of families completed (both twins) 31.9% 34.4% - - 33.3%
Partial returns (one twin completed) 260 376 - - 636
Data in the dataset (complete pairs) 397 617 - - 1014
Navigation Study Invitations sent 2009 3500 - - 5509
Battery completed by both twins 243 617 - - 860
Percentage of families completed (both twins) 12.1% 17.6% - - 15.6%
Partial returns (one twin completed) 328 543 - - 871
Data in the dataset (complete pairs) 234 595 - - 829