TEDS Data Dictionary

The Twin Web Activities

After logging in as described above, and after the consent form had been completed, each twin was presented with a screen containing links to their activities:

As illustrated above, the twin's name was displayed near the top of the page, along with a counter to show how many prize draw entries had been earned by the twin so far. Links to "rewards" and "information page" provided access to, respectively, an electronic copy of the flyer (not reproduced here) describing the prize draw and voucher rewards, and a twin-friendly version of the web study information sheet (pdf).

The twin activities were always presented in the order shown (top to bottom then left to right), and this was the order in which all twins were required to complete the activities. The "Introduction" comprised a short video (not reproduced here) containing brief instructions for carrying out the activities. Only links highlighted in red were active. The "Introduction" always remained highlighted because it could be repeated. In the example above, the link to "Yes/No" is also highlighted, because this is the twin's next activity. The previous 5 activities ("Dots and Numbers" through to "Number Sense") are greyed out because they have already been completed, so they cannot be started again. The remaining activities, from "Your School" onwards, would become highlighted in turn as the twin progressed. Moving the mouse over each activity name would reveal a message displaying the time that the activity was expected to take (these time ranges were based on measurements during piloting). The twin activities were as follows (click on the links to go to a detailed description of each web test):

In addition to the "Introduction", which is a general tutorial describing how all the tests should be conducted, each individual web test started with its own short tutorial. The test tutorials generally started with brief instructions for conducting the test (usually with audio and text, a few with animations), sometimes followed by one or more practice examples for the twins to try out. These practice items gave feedback, for instance pointing out the correct answer if the twin answered wrongly; such feedback was not given in any of the main test items.

Each twin was able to complete his/her activities independently - each had their own login, and could carry out their activities simultaneously on different computers if they wished. The progress of one twin would not be affected by the progress of the cotwin.

On completion of the final web test (Passages), each twin was presented with a screen congratulating them and informing them that a reward voucher would soon be on its way. This screen also gave each twin an opportunity to select their preferred voucher type, and reminded them that they had entries in any remaining prize draws.

General Test Rules

Each web test had its own set of specific rules, for example for scoring and discontinuing: these test rules are described in detail in the pages for each web test (see links above). However, there were several general test rules that affected most or all of the tests. These rules were programmed into the web tests, and were enforced automatically. The rules were as follows:

• One attempt at each activity.
  Each of the web activities (not including the Introduction) could be attempted once and only once by each twin. There was no mechanism for re-setting activities, even if parents or twins were aware of problems and asked for activities to be repeated.
• One attempt at each test item.
  Every item in each of the cognitive web tests could be attempted once and only once by each twin. If a twin attempted to repeat a test item, for example by clicking the "Back" button in the browser, then the test would be stopped and the twin would be presented with a message explaining the problem - although see "abandoned tests" below. The twin could then resume the test as usual from the menu of activities. (Use of the "Back" button was however allowed in the four environment and wellbeing questionnaires.)
• Come Back Later.
  In each item of most web tests (except Yes/No, Dot Number, Number Sense, Reaction Times and PVT), and on each page of the four questionnaires, there was a "Come Back Later" button. Clicking on this button would halt the web activity. The twin could then resume the activity at any later time, by selecting it from the menu of activities in the usual way. The twin would then continue at the same item/page in which they had clicked "Come Back Later". This facility was provided to allow for interruptions to the twins during activities, and to make the activities as flexible as possible in terms of time (for example, a twin could complete an activity in one go, or in several sessions spread over different days).
• Timing out during test items.
  Some but not all of the web activities had built-in timeouts. The timeout mechanisms varied between activities, and are described in detail in the individual web activity pages linked above. Some activities (the questionnaires, Passages, Vocabulary, Number Line, Corsi Block) would not timeout at all. In the other tests, timing out would generally result in the item being forfeited with zero score and either a missing response or a coded response value, depending on the test. After timing out, in most tests the item would be replaced on screen with a "next item" screen. The twin could then resume the test at the next item by clicking on this. Exceptions are the Dot Number and Reaction Times tests - instead of a screen with a "next item" button, the next test item would automatically be presented on screen.
• Timing out generally.
  The web site as a whole had a built-in session timeout of 15 minutes, which applied on introductory pages such as the consent form and twin menu of activities (but did not apply during the twin activities themselves). This means that after 15 minutes with no activity (no clicking on the screen), the session would end and a twins or parent would be logged out. They were then taken back to the login page. This timeout was a routine security measure, to protect logged in sessions.
• No feedback.
  During the tests, no feedback was provided to tell twins whether they had answered each item correctly or incorrectly, or to give twins any idea of their overall score in a test. A twin's route through a test, determined by branching or discontinue rules (if any), was always hidden from the twin. The no-feedback rule was partly a means of preventing "cheating" or collaboration between twins; it was also intended to avoid causing discouragement to twins that might be caused by repeated feedback about incorrect answers.
• Abandoned tests.
  Four of the tests (Yes/No, Dot Number, Number Sense, Reaction Times) were programmed to run entirely in the browser, until the end of the test when the data were sent back to the server. As a result, any interruption of these tests would cause the test to fail or be "abandoned". This could occur if the twin's computer crashed, or if the internet connection was lost at the conclusion of the test, or if a temporary problem occurred on the server, or if the twin halted the test by closing the browser, or by clicking the browser's Back or Refresh buttons. The web site was programmed to recognise abandoned tests, and to deal with them as follows. Firstly, the test would be marked as abandoned so that it could not be repeated or restarted - the twin would move on to the next activity, and be credited with a prize draw entry. Secondly, any residual data from the test would be deleted, so it would not be exported in the analysis file and would not form part of the dataset.

Web Callers

Some families in cohort 1 were assigned to web callers (see the main 16 Year page for a further description). These callers were staff employed by TEDS to telephone the families during the web study. The callers fulfilled various functions:

• Collection of verbal consents (or opt-outs) for the web study.
• Encouraging families to complete the web tests, by talking to parents or to the twins themselves.
• Offering basic technical support to the families, to help with completion of the web tests (for example, help with use of a browser, or identifying whether or not a family's computer met the necessary requirements).
• Collection of feedback from the families. This was not done systematically, but any feedback offered by families was passed back to TEDS by callers.
• Collection of any other relevant family details communicated by the families, for example changes of address, or twin medical conditions.

Callers were required to keep track of their allocated families using specially-designed pages in the TEDS web site. Each web caller was issued with their own login (username and password) for the web site. Once logged in, web callers could view detailed information describing the web activity of families allocated to them, for example how far each twin had got in each web test, and the dates and times when test items had been attempted.

Other information collected from families by web callers, such as opt-outs and changes of address, were communicated to the TEDS office by telephone, email or post. Web callers were encouraged to refer back to the TEDS office if unable to help families themselves with particular problems.