TEDS Data Dictionary

Description of Test

The test consisted of a series of reading comprehension questions. For each question, there were four possible responses; the twin selected a response by clicking on it on the screen. There were 36 items: the questions and responses are tabulated further down this page in the table of items. Any given twin taking the test may have been presented with fewer than 36 items, because of the branching and discontinue rules, which are described under the next heading.

Each item is matched to a level (2 to 7) for English in the National Curriculum. The table of items on this page shows the level for each item. Items are presented in increasing order of difficulty, so level 2 items are presented first, then level 3 items, and so on. In the branching rules, each branch occurs at the start of a new level (see below).

This test was unaffected by item timeouts.

Test Rules

• Scoring
  For each question, the correct response is given a score of 1, and any of the three incorrect responses is given a score of 0.
  Any items skipped due to upward branching (see below) are credited with a score of 1, as if they had been answered correctly.
  The maximum total score for the test is 36.
• Branching rules
  The test contains 5 branch points. Each branch point consists of the first three items at a given level (except for level 7). The branch points are listed in the table below. The general principles of the branching are as follows:
  • Items are attempted in ascending order of item number; these items are grouped by level (2, 3, 4, 5, 6, 7). The rules below apply to levels 2 to 6; there is no branching at level 7.
  • Start with the first three items at each level.
  • If at least one of the first three items is incorrect, proceed to the remaining items at the same level. Then start the next level.
  • If all of the first three items are correct, skip the remaining items at that level (crediting them as though they had been answered correctly), and start the next level.

  Branch	Level	Branch point items	If all correct, go to:	If any incorrect, proceed to items:
  1	2	1-3	branch 2 (items 7-9)	4-6
  2	3	7-9	branch 3 (items 14-16)	10-13
  3	4	14-16	branch 4 (items 19-21)	17,18
  4	5	19-21	branch 5 (items 25-27)	22-24
  5	6	25-27	level 7: items 32-36	28-31

• Discontinue rule
  Discontinue the entire test after any four consecutive incorrect items at any given level. Note that this only applies within a level; the discontinue rule is re-set at the start of each new level.

Item Variables

The item variables relating to the GOAL 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. Note also that the variable holding the total test score was also generated automatically on the web server, so this is treated as an item variable, not a derived variable.

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 skipped and credited due to upward branching, the item response variable is recoded from missing to -3 (the item score is already recorded as 1 on the web server).
• 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 instances of crashed or otherwise compromised tests, the status flag is recoded from 2 to 3, the data flag is recoded from 1 to 0, and all item variables are recoded to missing (test data deleted)
• 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

The numbering of the items, shown in the table below, equates to the numbering used in the item variables. Note that this is not necessarily the same as the order in which items were presented to twins in the test (see test rules above).

The "reference" column contains a coded string of the form X-YY-Z, containing the following information:
X: the item number in the original GOAL measure
YY: skill evaluated (CP = comprehension, EA = evaluation and understanding)
Z: item type (W = word, S = sentence, T = text)