TEDS Data Dictionary

Description of Test

This web test is based on the Mill Hill vocabulary scale. Note that this is a quite different vocabulary test from the WISC-III test used at earlier ages.

The test consists of a series of multiple choice questions. In each question, a single word is presented at the top of the screen. Below it, 6 other words, labelled A, B, C, D, E and F are presented as the response options. Twins respond by clicking on the response they think is closest in meaning to the word at the top of the screen. There is only one correct response for each question. The stimulous and response words for each question are tabulated in full in the table of test items below.

The 33 items are presented in numerical item number order, without branching. The test is discontinued if 7 consecutive items are answered incorrectly. There is no time limit for responding to each item, so item timeouts do not occur. A "come back later" button is presented on screen for all items.

Test Rules

• Scoring
  For each item, the correct response is given a score of 1, and any other response is given a score of 0. Any question omitted due to the discontinue rule is given a score of 0. The total test score is the sum of the item scores. The maximum total score for the test is 33.
• Discontinue rule
  Discontinue the test after seven consecutive items are answered incorrectly (with zero score).

Item Variables

The item variables relating to the Mill Hill vocabulary test, as listed in the table below, were generated automatically by programs on the web server during the course of the test. Note that the dataset only includes data for completed tests. If a twin started the test but left it unfinished, then the data for the test were not used.

In most cases the values of these variables have been left unaltered, although some have been recoded during data cleaning as follows. See the web data cleaning page for further details.

• For items skipped due to the discontinue rule, the item response variable is recoded from missing to -2, and the item score is recoded from missing to 0.
• For items that crashed or malfunctioned in any way, the item response variable is recoded from missing to -4, and the item score is recoded from missing to 0.
• For twins identified as random responders in this test, the status flag is recoded from 2 to 4, the data flag is recoded from 1 to 0, and all item variables are recoded to missing (test data deleted)

The test start and end dates and times, and item answer and download times, have not been retained in the dataset.

Test Items