TEDS Data Dictionary

Description of Test

This was an extended version of the Mathematics web test that was previously used in the 10 Year study. The 10 Year version of the test was extended by the addition of 6 harder items (at National Curriculum level 8) at the end of each of the three sub-tests. In addition, the branching rules were modified for sub-test 2. In other respects, the test was unchanged.

The test consisted of a series of mathematics questions. The questions are presented in full in the table below.

The question format varied from item to item. Some questions required a numerical response, where the twin had to type a number in a box then click on "OK". In other questions, a set of possible responses (consisting of pictures, text or numbers) were presented on screen, and the twin had to select one or more answers. In these cases, if one answer was required then the twin simply clicked on it; if two or more answers were required, the twin clicked on the chosen responses then clicked on "OK".

The test comprised 3 sub-tests:

1. Understanding number (33 items)
2. Non-numerical processes (25 items)
3. Computation and knowledge (37 items)

The items from the different sub-tests were intermingled in the test as a whole. A twin was presented with an item from sub-test 1, then an item from sub-test 2, then an item from sub-test 3, and so on. However, the branching and discontinue rules (described below) applied independently within each sub-test. Hence a twin might branch up in one sub-test while branching down in another; and a twin might continue with items from one sub-test after another sub-test had discontinued.

Test Rules

• Scoring
  For each question, the correct response is given a score of 1, and any incorrect response is given a score of 0. The maximum total score for the test is 95.
  If at any point in a sub-test a twin branches up, and does not subsequently branch down again, then any lower items skipped due to branching (in the same sub-test) are credited towards the score, as though they had been answered correctly.
• Branching rules
  The branching rules apply independently within each of the sub-tests. The detailed branching rules for each sub-test are tabulated below, but the general principles of the branching are as follows:
  • A branch point consists of 3 selected consecutive items (in item number order) in a sub-test.
  • Each sub-test has two branch points:
    1. The first branch point occurs at the very start of the sub-test, and is placed at an intermediate level of difficulty (National Curriculum Level 4 or 5).
    2. The second branch point is placed at a higher level of difficulty (National Curriculum Level 6).
  • If the three items of a branch point are all answered incorrectly, move down to a basal point at a lower level.
  • If some items of a branch point are answered correctly and some incorrectly, move on to the basal point directly following the branch point.
  • If all three items of a branch point are answered correctly, then:
    1. For the first branch point,
       move up directly to the second branch point.
    2. For the second branch point,
       move on to the basal point directly following the branch point.
  • At a basal point, the twin proceeds upwards (in ascending order of sub-test item number) either until the end of the sub-test is reached, or until the twin discontinues the sub-test (see below). Note that the 3 items of the second branch point are treated as normal items (not branching items) if they are reached by continuation after a basal point.
  The exact branching rules for each sub-test are tabulated below:

  Sub-test	Branch	Branch point items	If all incorrect go to:	If some correct go to:	If all correct go to:
  1	1	1401, 1402, 1403	Basal point 1101	Basal point 1404	Branch point 1601, 1602, 1603
  	2	1601, 1602, 1603	Basal point 1404	Basal point 1604
  2	1	2501, 2502, 2503	Basal point 2101	Basal point 2504	Branch point 2605, 2606, 2701
  	2	2605, 2606, 2701	Basal point 2504	Basal point 2801
  3	1	3401, 3402, 3403	Basal point 3101	Basal point 3404	Branch point 3601, 3602, 3603
  	2	3601, 3602, 3603	Basal point 3404	Basal point 3604

  No item is presented more than once, and no further branching occurs after a basal point has been reached. Here is an example sequence of items in sub-test 1:
  1401, 1402, 1403 (branch up), then 1601, 1602, 1603 (branch down), then 1404 upwards (omitting 1601-1603 as already attempted) until discontinuing; items 1101 up to 1304 are credited because they were skipped due to upward branching.
• Discontinue rule
  Discontinue the sub-test after three consecutive items are answered incorrectly (with zero score). Note that this rule does not apply while in a branching point: if the three consecutive items of a branch point are incorrect, then a downward branch occurs rather than discontinuing (see above). The discontinue rule only applies after a basal point has been reached, as described above.
  The discontinue rule applies independently within each sub-test. Hence one sub-test may discontinue while the other sub-tests continue.
• Timeout rule
  A timeout of 5 minutes applies to each item. After 5 minutes with no response, the item is forfeited with zero score, and a "next item" screen appears. On resuming the test, the twin is taken to the next item in sequence as described above.

Item Variables

The item variables relating to the Maths 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 that the variable holding the total test score was also generated automatically on the web server. It is therefore treated as an item variable (it did not have to be derived as at age 10).

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.

• Where possible raw item response strings have been converted or recoded into numeric values or categories.
• For timed out items, the item response variable is recoded from missing to -1, and the item answer time is recoded from 300 to missing (item scores are 0)
• 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.

* XXX is the item number, as tabulated below.

Item numbering and item references

This section explains the meaning of the item numbers and reference numbers, which are shown in the first two columns of the table of items below. The item numbers (shortened from 4 to 3 digits) are also incorporated into the item variable names, as described above.

Each item number comprises 4 digits, of the form AB0C as follows:

• A (first digit): this identifies the sub-test (1, 2 or 3).
• B (second digit): this identifies the National Curriculum Level of the item, according to the NFER booklets from which the items were taken. The levels are 1, 2, 3, 4, 5, 6, 7 and 8. The higher the level, the greater the difficulty of the question.
• 0 (third digit is always a zero)
• C (fourth digit): these are arbitrary sequence numbers, to distinguish between items in the same sub-test and at the same National Curriculum Level.

For the variable names tabulated above, the item number is shorted to ABC (the third digit, zero, has been removed).

The reference numbers shown in the table below can be used to identify the NFER booklet items that were used for this test (see the 12 year measures page for full details of the booklets used). Each reference has the form YY-ZZ as follows:

• YY is the NFER booklet number: 6, 7, 8, 9, 10, 11, 12, 13 or 14
• ZZ is the item number within the given booklet. These item numbers range from 1 to roughly 50.

Test Items

Item no.	Ref.	Item text	Picture	Correct response	Raw response coding
1101	7-7	This is a number pattern. Type the next three numbers in the boxes. 4 , 4 , 3 , 4 , 4 , 3 , 4 , __ , __ , __	(no picture)	need all 3 answers in the correct sequence: 4, 3, 4	String: numbers as entered, recorded as x|y|z|
1201	7-3	Find two odd numbers that add up to 8. Type these numbers in the boxes. Remember, both numbers must be odd.	(no picture)	one of the following: 1 + 7, 7 + 1, 3 + 5, 5 + 3	String: numbers as entered, recorded as x|y|
1202	7-16	One of these squares has one quarter coloured orange. Click on it.		the bottom-left shape (3rd option)	Numeric: shapes coded 1, 2, 3, 4 (top-left to bottom-right)
1203	9-41	Type these numbers in the boxes in order, starting with the smallest. 60, 16, 6, 66, 36	(no picture)	need all 5 correct, in the right order: 6, 16, 36, 60, 66	String: numbers as entered, recorded as v|w|x|y|z|
1301	8-16	Look at this number pattern. Type the missing numbers in the boxes. __ , __ , 9, 12, 15, 18	(no picture)	need both correct, in the right order: 3, 6	String: numbers as entered, recorded as x|y|
1302	8-17	Type in the box the figures for the number two hundred and fifty two.	(no picture)	252	Numeric: number as entered
1303	8-32	Look at the numbers. Find the number that is closest to 77 and click on it.		75 (4th option)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right)
1304	9-1	Type in the three missing numbers in this pattern. __ , 10, 15, __ , __ , 30, 35	(no picture)	need all 3 correct, in the right order: 5, 20, 25	String: numbers as entered, recorded as x|y|z|
1401	8-8	A girl was born on the 8th of April 1980. How old was she on the 8th April 1993? Type in the answer.	(no picture)	13	Numeric: number as entered
1402	9-38	What fraction of the shape is shaded? Click on the answer.		¼ (one quarter)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right)
1403	8-34	You are going to break this bar of chocolate into four quarters. How many squares will there be in each quarter? Type in the answer.		3	Numeric: number as entered
1404	9-28	Click on the correct answer. 27 to the nearest 10 is__		30 (3rd option)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right)
1501	8-23	Work out the answers and type them in the boxes. 7 x 100 = __ 14 x 100 = __ 37 x 100 = __	(no picture)	need all 3 correct, in the right order: 700, 1400, 3700	String: numbers as entered, recorded as x|y|z|
1502	8-28	Type the missing number in the box. 15 x 6 = 90 __ x 6 = 96	(no picture)	16	Numeric: number as entered
1503	9-16	Look at the number 6085. Change the order of the figures around to make the biggest number possible. Type in the answer.	(no picture)	8650	Numeric: number as entered
1504	10-16	Fill in the missing numbers by typing in the boxes. __ + 1 = 11 __ - 1 = 11 __ x 1 = 11	(no picture)	need all 3 correct, in this order: 10, 12, 11	String: numbers as entered, recorded as x|y|z|
1505	10-19	Which of these lengths is closest to the length of a real bath? Click on it.		2.2m (2nd option)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right)
1506	10-24	Type 17, 36 and 612 in the correct boxes.		either of these two correct sequences: 612, 17, 36 or 612, 36, 17	String: numbers as entered, recorded as x|y|z|
1507	10-29	Click on the box in which the times are in the order that they occur in a day.		the top (1st) option	Numeric: responses coded 1, 2, 3, 4 (top to bottom)
1601	8-31	Type the missing number in the box. 27 + 27 + 27 + 27 + 27 = 27 x ___	(no picture)	5	Numeric: number as entered
1602	9-11	The first machine multiplies all numbers by 6. The second machine changes them all back again. Click on what the second machine does.		÷6 [divide by 6] (4th option)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right)
1603	9-17	Estimate how much orange juice there is in this jug. Give your answer in millilitres. Type in the answer		any number in the range 230 to 340	Numeric: number as entered
1604	11-36	Type the correct number in each box.		need all four correct: 0, 0, 1, 1	String: numbers as entered, recorded as w|x|y|z|
1701	10-39	This shows part of a tape measure. What length is marked by the arrow, in metres? Click on the answer.		1.79m (1st option)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right)
1702	11-30	Type in the answer. 1.25 x 100 = ___	(no picture)	125	Numeric: number as entered
1703	11-44	These three numbers are alike in some ways: 9, 36, 81. Click on the two ways in which they are alike.		Need both correct: They can all be divided exactly by 3 (2nd option), They are all square numbers (5th option)	String: two responses selected, recorded as x|y| (response options are numbered 1 to 6, top to bottom)
1704	11-47	What fraction of this circle is shaded? Click on the answer.		1/8 [one eighth] (1st option)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right)
1801	12-41	Complete the table below for the equation y = 2x - 3		need both correct answers, in the right sequence: 3, 5	String: numbers as entered, recorded as x|y|
1802	14-29	The numbers put into this machine are combined and come out as a single number. The table shows what has happened for some numbers. Complete the last line of this table.		52	Numeric: number as entered
1803	14-37	Work out the value of x. Click on your answer.		4.5 (third option)	Numeric: responses coded 1, 2, 3, 4, 5 (left-to-right, top then bottom)
1804	13-47	Denise has thought of two numbers. The numbers added together make 23. The smaller number subtracted from twice the larger number makes 22. What are Denise's numbers?	(no picture)	need both correct (in either order): 8, 15	String: numbers as entered, recorded as x|y|
1805	14-42	A straight line joins the point (4,6) to the point (10,18). What are the coordinates of the mid-point of the line?	(no picture)	the coordinates must be in the correct order: (7,12)	String: numbers as entered, recorded as x|y|
1806	14-48	Look at this graph. Which one of these could be the equation for the graph? Click on your answer.		B: y = x - 2 (second option)	Numeric: responses coded 1, 2, 3, 4, 5, 6 (left-to-right, top then bottom)
2101	7-1	Which is the longest drinking straw? Click it.		3rd straw down from the top	Numeric: responses coded 1, 2, 3, 4 (top to bottom)
2201	6-4	One of these shapes has four corners that are the same. Click on this shape.		the bottom-left shape (rectangle)	Numeric: responses coded 1, 2, 3, 4 (left to right, top then bottom)
2202	6-9	One of these shapes does not have three sides. Click on this shape.		the middle-bottom shape	Numeric: responses coded 1, 2, 3, 4, 5 (left to right, top then bottom)
2203	8-4	This man is walking along a path. When he comes to the letter B, he turns right and walks a little further. Which letter does he come to? Click on it.		E (bottom of diagram)	Numeric: responses coded 1=A, 2=B, 3=C, 4=D, 5=E
2204	9-3	Click on each shape that has only 1 curved side and 2 straight sides.		need both correct: the top-right and bottom-left shapes (3rd and 4th options)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right, top then bottom)
2301	9-45	Click on the shape with the largest number of right-angled corners.		the bottom-middle shape (5th option)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right, top then bottom)
2501	10-26	Which card appears the same when turned upside down? Click on it.		8 of diamonds (top-middle picture)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right, top then bottom)
2502	9-23	The picture below shows half of a symmetrical pattern. Click on the picture opposite which shows the other half of the pattern.		the top-right picture (3rd option)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right, top then bottom)
2503	8-9	I start at the place marked with an A and walk South-West. Click on the number I come to.		3	Numeric: responses coded 1, 2, 3, 4, 5 as shown in picture
2504	11-31	These shapes are alike in some ways. Click on 2 ways in which they are alike.		need both correct: they all have 4 sides (1st option), they all have at least 1 right angle (4th option)	String: two responses selected, recorded as x|y| (response options are numbered 1 to 5, top to bottom)
2505	11-40	Three corners of a square are found at P (4,5), Q (2,3), R (4,1). Where is the fourth corner? Type in the answer.		Need both correct, in the right sequence: (6, 3)	String: numbers as entered, recorded as x|y|
2601	8-18	The letter E is turned clockwise through one right angle. Click on the answer.		the bottom-right (3rd) option	Numeric: responses coded 1, 2, 3 (left to right)
2602	8-30	Look at the four different kinds of shapes. Imagine fitting shapes of the same kind together. Without leaving gaps, which of these shapes will fit together with shapes of the same kind? Click on the shape(s). There may be more than one.		need all 3 correct: 1st, 2nd and 3rd options	String: up to four responses selected, recorded as x|y|z| (response options are numbered 1 to 4, left to right)
2603	9-15	Click on the reflection of this shape.		the 2nd shape from the top	Numeric: responses coded 1, 2, 3, 4 (top to bottom)
2604	9-27	Click on the 2 shapes that have the same area.		need both correct: the top-left (1st) shape, the bottom-left (4th) shape	Numeric: responses coded 1, 2, 3, 4, 5 (left to right, top then bottom)
2605	9-33	The shape below is about to turn 3 right angles anticlockwise. Click on where the dot will be on the shape opposite.		the top-right square	Numeric: responses coded 1, 2, 3, 4 (left to right, top then bottom)
2606	11-42	Which of these shows a reflection? Click on it.		the top-right pattern (2nd option)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right, top then bottom)
2701	11-35	Mark all the angles that are equal to X. Click on the arrows in the picture that point at the angles you think are the same as X.		need all three answers: the angle directly opposite X, and the two acute angles in the bottom-right corner	String: grid numbers representing areas clicked on the image, recorded as x|y|z|; the three correct responses are grid references 26, 33, 41
2801	10-35	A man walked around this building. He drew a sketch at each point. What point was he at when he drew these sketches? Click on the correct letter for each sketch		need all three answers: B (top diagram), A (bottom left), C (bottom right)	String: grid numbers representing areas clicked on the image, recorded as x|y|z|; the three correct responses are grid references 32, 65, 71
2802	13-28	Click on one line on this shape to show it split into two congruent parts.		anywhere on the fourth vertical line from the left (right-hand side of the third square from the left)	String: grid number representing the area clicked on the image, recorded as x|; correct responses include grid references 37, 90, 105, 109, 126, 143, 160, 166, 177 (but it is not clear which part of the picture each refers to)
2803	13-36	Look at this shape. ABCD is a rectangle. P is halfway between C and D. Q is halfway between A and B. What fraction of rectangle ABCD is shaded? Click on the correct answer.		1/8 (third option)	Numeric: responses coded 1, 2, 3, 4 (left to right)
2804	13-35	This net can be made into a 3D shape. Click on the name of the shape.		cone (third option)	Numeric: responses coded 1, 2, 3, 4 (left to right)
2805	14-47	Only two of these nets can be folded up to make boxes without lids. Which nets are they? Click on them.		need both correct: the top-left shape, and the bottom-left shape (first and fourth options)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right, top then bottom)
2806	12-50	Look at this block of flats. Paul took a photograph of these flats from a helicopter flying directly overhead. What would these flats look like in his photograph? Click on the correct picture.		the bottom-middle shape (fifth option)	Numeric: responses coded 1, 2, 3, 4, 5, 6 (left to right, top then bottom)
2807	12-46	The letter X is always the same distance from point A. It is rotated through 360° around point A. It starts at point B and passes through points C, D and E. Work out the shape of the path it takes. Click on the name of this shape.		circle (fourth option)	Numeric: responses coded 1, 2, 3, 4 (left to right)
3101	6-2	Click on the shape which is below the square.		the oval shape at the bottom	Numeric: responses coded 1, 2, 3, 4, 5 (left to right, top to bottom)
3201	6-5	Double each of the numbers and type your answers in the boxes.		need all 3 correct, in this order: 4, 6, 8	String: numbers as entered, recorded as x|y|z|
3202	6-18	Work out the answer and type it in the box. 6 - 2 = __	(no picture)	4	Numeric: number as entered
3203	8-5	Click on each even number and then click on the OK button.		need all 3 correct: 8, 56, 44 (2nd, 4th and 5th options)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right)
3204	9-2	Natalie had 8 biscuits. She gave 6 to her friends. How many did she have left? Type in the answer.	(no picture)	2	Numeric: number as entered
3205	9-32	Click on each of the even numbers in the box.		need all 4 correct: 78 (top-left), 32 (top-right), 50 (bottom-middle), 10 (bottom-right)	String: grid numbers representing areas clicked on the image, recorded as w|x|y|z|; the four correct responses include grid references 1, 5, 6,11, 17, 59, 62 (but it is not clear which parts of the picture these relate to)
3301	8-2	30p has to be shared equally between 3 children. How much will each child receive? Type in the answer.	(no picture)	10	Numeric: number as entered
3302	9-9	Tapes cost £7 each. How much do 5 tapes cost? Type in the answer.	(no picture)	35	Numeric: number as entered
3303	9-19	What is the difference in price? Type in the answer.		5	Numeric: number as entered
3401	8-7	Look at this picture of Leon and Emma. What is the difference in height? Type in the answer.		5	Numeric: number as entered
3402	9-4	Mira sorts her money into piles. She has: four £1 coins, two 10p coins and five 2p coins. How much money does she have altogether? Click the answer.		£4.30 (2nd option)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right)
3403	8-11	What is the total cost of 6 books that cost £7 each? Type in the answer.	(no picture)	42	Numeric: number as entered
3404	8-15	What number is 3 less than 200? Type in the answer.	(no picture)	197	Numeric: number as entered
3405	8-19	Work out the answer to this sum and type it in the box. 64 + 905 = __	(no picture)	969	Numeric: number as entered
3406	8-35	One of these numbers can be divided exactly by five. Click on it.		65 (4th option)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right)
3407	9-14	Click on the hexagon.		the top-left shape (1st option)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right, top then bottom)
3408	9-30	What is the total of 680 and 192? Type in the answer.	(no picture)	872	Numeric: number as entered
3501	9-6	Type in the answer. 76 - 39 = __	(no picture)	37	Numeric: number as entered
3502	10-18	Type in the answer. 563 + 797 = __	(no picture)	1360	Numeric: number as entered
3503	11-21	Type in the answer. 149 + 785 = __	(no picture)	934	Numeric: number as entered
3504	11-23	Click on the time that is the same as 4:25 pm.		16:25 (the 4th option)	Numeric: responses coded 1, 2, 3, 4, 5 (top to bottom)
3505	11-43	Which of these is not a quadrilateral? Click on it.		A (the 1st option)	Numeric: responses coded 1, 2, 3, 4, 5 (left to right, top then bottom)
3506	11-50	What is the total cost of 8 books that cost £9 each? Type in the answer.	(no picture)	72	Numeric: number as entered
3601	8-14	Type in the answer. 47 x 2 = ___	(no picture)	94	Numeric: number as entered
3602	9-40	Type in the answer.		23	Numeric: number as entered
3603	9-44	84 stamps are shared equally between 6 children. How many stamps will each child have? Type in the answer.	(no picture)	14	Numeric: number as entered
3604	10-27	Jodie is making a model aeroplane. It takes her 1¼ hours to stick it together, and then ½ an hour to paint it. How long has it taken altogether? Click on the answer.		1 ¾ hours [one and three quarter hours] (4th option)	Numeric: responses coded 1, 2, 3, 4, 5 (top to bottom)
3605	10-30	All 4-sided shapes are called…? Click on the correct answer.		quadrilaterals	Numeric: responses coded 1, 2, 3, 4, 5 (left to right, top then bottom)
3701	10-21	Click on all the acute angles.		need both correct: top-left, bottom-left angles	String: up to five responses selected, recorded as x|y|z| (response options are numbered 1 to 5, left to right, top then bottom)
3702	10-41	Type in the answer.		54	Numeric: number as entered
3703	11-49	Which of these give the same answer? Click on them.		need both correct answers: 25% of £10 (1st option), ½ of £5 (2nd option)	String: up to four responses selected, recorded as x|y|z| (response options are numbered 1 to 4, top to bottom)
3801	12-3	Kerry has made this letter V for part of a display sign. Each square = 1cm². What is the area of the letter?		22	Numeric: number as entered
3802	12-4	How many different combinations of main meals and desserts are there? Type in your answer.		12	Numeric: number as entered
3803	13-46	This propeller has rotational symmetry. What is the size of the angle x? Type in your answer.		120	Numeric: number as entered
3804	14-33	Work out an approximate value for 802.6 / 3.8 by rounding 802.6 to the nearest ten and 3.8 to the nearest whole number. Type in your answer.	(no picture)	200	Numeric: number as entered
3805	13-32	In a box there are the following packets of crisps: 7 chicken, 4 salt and vinegar and 2 cheese and onion. Anna takes out a packet without looking. What is the probability that it is cheese and onion? Click on the correct answer.		2/13 (second option)	Numeric: responses coded 1, 2, 3, 4 (left to right)
3806	13-29	A crate holds 18 bottles. How many crates are needed to hold 666 bottles? Type in your answer.	(no picture)	37	Numeric: number as entered