TEDS Data Dictionary

The 10 Year PIAT Web Test

Contents of this page:

Introduction

The page describes a version of the PIAT (Peabody Individual Achievement Test) that was used in the 10 Year twin web study battery.

Description of Test

This is a test of reading ability. In each item of the test, the twin is first presented with a sentence of written text to read on the screen; this is then removed, and replaced with four pictures. The twin is required to select (by clicking) the picture that most accurately matches the sentence they have read. The sentences and pictures for all items are tabulated below.

There is a time limit of 20 seconds (shown pictorially by a moving time bar on screen) for reading the sentence for each item. If 20 seconds passes before the twin has clicked "OK" on the screen, then the twin is automatically moved forward to the pictures. It is not possible for the twin to go back to the sentence once the pictures have appeared.

There is another time limit of 20 seconds for responding (by clicking on a picture). If 20 seconds passes before the twin has clicked on a picture, this is treated as an incorrect response (zero score), and then the twin is shown a prompt asking them to continue with the next item.

The test includes 89 items, as follows:

  • 2 "reading recognition" items (R4, R5), in which the text consists of a single word. These are treated as warm-up items, as they do not contribute either to the branching or the scoring of the test as a whole.
  • 5 "practice" items (P1, P2, P3, P4, P5), in which the text consists of simple short sentences. These form part of the branching mechanism, as described below, but do not contribute to the overall score of the test.
  • 82 main items (numbered 19 to 100).

Most twins will attempt fewer than 89 items, because of the branching and discontinue rules (see below). The items are numbered in increasing order of difficulty, with item 100 intended to be the most difficult item.

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.
    The maximum total score for the test is 82: this score only includes the main items (19-100) not the reading recognition items (r4, r5) or the practice items (p1-p5).
    If at any point a twin branches up, and does not subsequently branch down again, any lower items skipped due to branching are credited towards the total score, as though they had been answered correctly.
  • Branching rules
    The branching rules for this test are complex, and are tabulated in full below. The general principles of the branching are as follows:
    • There are 7 branch points in the test. Each branch point consists of 3 consecutive items (except for the first branch point, which consists of the 5 practice item P1-P5).
    • If all (3 or 5) items in the branch point are answered correctly, move up to the next branch point or basal point as appropriate.
    • If one or more items in the branch point are answered incorrectly, move down to the appropriate basal point (or in one case to a lower branch point).
    • At a basal point, the twin proceeds upwards either until the end of the test is reached (item 100), or until the twin discontinues (see below).
    The exact branching rules are tabulated below. For all twins, the test starts with (non-branching) items R4 and R5, followed by branch point items P1-P5.
    Branch point itemsIf all correct, go up to: If any incorrect, go down to:
    P1-P5Branch point 40-42Basal point 19
    28-30Basal point 31Basal point 19
    40-42Branch point 52-54Branch point 28-30
    52-54Branch point 64-66Basal point 43
    64-66Branch point 76-78Basal point 55
    76-78Branch point 88-90Basal point 67
    88-90Basal point 91Basal point 79
    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: p1-p5 (branch up), then 40-42 (branch up), then 52-54 (branch down), then 43-51, then 55 upwards including items 64-66 until discontinuing.
  • Discontinue rules
    Discontinue the test after five scores of zero in any seven consecutive items. This rule only applies after a "basal point" has been reached (it does not apply within branch points).
  • Timeout rules
    Each item has two time limits: 20 seconds for reading the initial sentence, then 20 seconds for choosing an answer (by clicking on a picture). On both the text screen and the picture screen, a moving time bar is displayed to shown the passing of the 20 second limit. The timeouts are enforced as follows.
    • In the text screen, if 20 seconds passes before the twin has clicked on "OK", then the text screen is automatically replaced by the picture screen. It is not possible for the twin to return from the pictures to the text.
    • In the picture screen, if 20 seconds passes before the twin has clicked on a picture, then the item is forfeited (with zero score). The pictures are removed from the screen, and replaced by a link to the next item, allowing the twin to continue with the test.
  • Come Back Later restriction
    The "Come Back Later" button was only provided on the text page for each item, not on the pictures page. This was to prevent twins from looking at the pictures then going back to the text to double-check before answering. If a twin ended a session (for example by closing the browser) while on a pictures page, then the item would be forfeited with zero score; on resumption, the twin would be presented with the text for the next item.

Item Variables

The item variables relating to the PIAT 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 timed out items, the item response variable is recoded from missing to -1, and the item answer time is recoded from 20 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, and the item score is recoded from missing to 1.
  • 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 reading, answer and download times, and item orders, have not been retained in the dataset.

VariablesExplanationValues
jpstat1/2 Test status: outcome of test 0=not started, 1=started but not finished, 2=successfully completed, 4=random responses
jpdata1/2 Data flag: is test data present in the dataset? 0=no, 1=yes
jpstdt1/2 Start date of the test [not in dataset] Date values
jpsttm1/2 Start time of the test [not in dataset] Time values
jpenddt1/2 End date of the test [not in dataset] Date values
jpendtm1/2 End time of the test [not in dataset] Time values
jpsess1/2 Number of sessions (at the computer) used by the twin to complete the test. Integer values of 1 or above
jptime1/2 Time taken to complete the test, in seconds Integer values (number of seconds)
jpXXa1/2
(XX is the item number: r4, r5, p1-p5, t19-t100)
Item responses (picture numbers, as tabulated below) 1/2/3/4 (picture selected) or -1=timed out, -2=discontinued, -3=credited due to upward branching, -4=item crashed
jpXXs1/2
(XX is the item number: r4, r5, p1-p5, t19-t100)
Item score (see table of items below for details) 0=incorrect, 1=correct
jpXXrt1/2
(XX is the item number: r4, r5, p1-p5, t19-t100)
Reading time: length of time (in seconds) taken by the twin to read the text before clicking on OK [not in dataset] Integer values (number of seconds)
jpXXat1/2
(XX is the item number: r4, r5, p1-p5, t19-t100)
Answer time: length of time (in seconds) taken by the twin to select a picture [not in dataset] Integer values (number of seconds)
jpXXdt1/2
(XX is the item number: r4, r5, p1-p5, t19-t100)
Download time: length of time (in seconds) between the end of the previous item and the start of this item; time needed to download files for this item [not in dataset] Integer values (number of seconds)
jpXXo1/2
(XX is the item number: r4, r5, p1-p5, t19-t100)
Order or sequence of this item in the test; dependent on the branching path taken by the twin through this test [not in dataset] Integer values of 1 or above

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 the same as the order in which items were presented to twins in the test (see branching rules above).

itemtextcorrect picturepictures
R4Swimming2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
R5Castle4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
P1This is a girl4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
P2It is a dog1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
P3It is a red duck3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
P4The bird is in the tree 2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
P5See the boy with the hat. 3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
19There is the sun.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
20A boy is on a bike.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
21Here is a fire.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
22The can is going into a bag.1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
23The puppy is in the pan.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
24Some kittens are in the bed.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
25The pony has a big hat on its head.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
26In the window is a toy.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
27A bird is on the horse’s back.1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
28A cake is sitting on the step.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
29The animal has put the people into a cage.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
30A cookie is running out of the store. 4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
31The tiger has a feather in its mouth.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
32It is a surprise to see a bus bringing chickens to school. 1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
33The monkey is holding a rocket with its tail.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
34Grandmother finds a lion in the garden.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
35Inside the basket is a pair of skates.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
36The woman on television is smiling.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
37A pie is burning so the kitchen is full of smoke.1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
38The clown is throwing paper aeroplanes at the family. 4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
39A kite string is caught on the telephone line.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
40A bull has chased the farmer up the ladder and onto the roof. 4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
41A wheel of the tractor is stuck in the pond.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
42Whoever built this kennel made many mistakes.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
43A strange creature from a faraway planet is ringing the doorbell.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
44The tired giraffe has put its pillow on the cabin and is taking a nap.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
45While leaning against a log, the elf is taking a bite out of a banana.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
46These crows are not frightened by the scarecrow in the cornfield.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
47A ghost is practising the flute beneath a balcony.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
48The lost girl found large tracks in the sand.1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
49Dusty spider webs have given the unused castle a scary look. 2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
50The eagle floats on its wings as it travels in search of a feast.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
51The fallen branch caused the runner to stumble.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
52The windscreen on the wrecked taxi was not destroyed. 1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
53His foolish costume delights everyone except his daughter. 1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
54Swooping off its perch, the thief seized the sausages in its claws.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
55A scarf and cane are hanging from the closet rod.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
56Postage stamps may be created to remind us of historical military occasions.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
57Its ivory horn outlined against the sky, the unicorn poses on the horizon.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
58The weary hikers stagger through the rugged passage. 4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
59The aquarium provides an entertaining display in the barbershop.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
60The delightful scenery is scarred with rusting junk and machinery.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
61The wretched villain is confined to the dingy dungeon. 2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
62The knight in armour steers the rickety raft over the waterfall.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
63A peasant attempts to wrestle his heavy cabinet into a wheelbarrow.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
64An octopus is in a panic over a painful visit from a hornet. 1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
65Awaiting the safety of twilight, the vampire crouches in the corncrib.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
66The barefoot acrobat, showing tremendous grace, stirs the audience to applause.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
67The gorilla is fascinated by its deformed image in the mirror.1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
68The stranger hesitates because the ancient building appears haunted.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
69The bulldozer did not detour but invaded the banquet area. 3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
70A robot monitors the radar terminal while operating the throttle of the aircraft.1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
71The cargo is being hauled down the wharf to a waiting barge. 1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
72The vacant kennels are overgrown with briars and saplings. 2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
73The inexperienced senator was now being bombarded with numerous inquiries.1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
74The barricade, which encircles the fortress, contributes an effective obstacle to intruders. 4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
75The residence has been essentially reduced to rubble, the remainder being only the foundation. 4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
76Binoculars on a tripod can be exploited to contemplate constellations in a galaxy.1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
77From the belfry, a raven spies on a heifer grazing near the quarry.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
78This beast has devoured such a quantity of lush fodder that it is now inactive.1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
79The lecturer is distributing pamphlets to an unruly faculty. 3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
80The wispy seeds are so downy that, once relinquished, they soar off with the slightest disruption.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
81The barrier that is interfering with entry to the motorway is a sedan.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
82The displeased chauffeur had to remove the luggage prior to replacing the punctured tyre.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
83After a dazzling performance, the successful athlete is suffering from exhaustion. 1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
84A sturdy muskrat is mowing countless thistles.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
85Because of a collision in the intersection, the constable has veered into the pedestrian zone.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
86Heedless of the precipitation, the residents of the community evacuated as the volcano erupted.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
87Complete with gala decorations, the buffet is the occasion for a raucous reunion of exuberant alumni.1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
88Disregarding his responsibility, the barker fends off the Doberman pinscher that is harassing him. 3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
89This cypress, once vigorous and magnificent, now is decomposing among the vegetation. 4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
90Through the protracted, seemingly interminable tempest, one can perceive disarray: the trellis askew and the conifers bowed. 4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
91Light radiating through the playhouse portal projects elongated silhouettes of the belated patrons onto the adjoining facility. 2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
92Because of the contrasting physical images and preferred pursuits of these juveniles, others are astonished when informed that they are twins.3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
93The valise is disreputable – antiquated, crammed imprudently with apparel, and secured with frayed twine.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
94The adolescent, survivor of an unavoidable calamity, applies antiseptic to a limb to eliminate possible infection.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
95A forlorn politician ascends the escalator to the privacy of her capitol suite.1PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
96The verdant countryside is prodigiously arable; however, a squalid domicile sullies the otherwise exquisite panorama.4PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
97The pollster is perturbed by the flippant observations of the minstrel she is interrogating. 3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
98The immaculately attired socialite was staggered by ascertaining that she had inadvertently exchanged her shampoo for a nostrum that eradicated her locks.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
99A raconteur, the picture of sartorial resplendence, has a ponderous and histrionic barrister cajoling an adjudicator for clemency. 3PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image
100When the official signified the transgression, anguished zealots hurled acrimonious invectives and engendered pandemonium.2PIAT test item imagePIAT test item image
PIAT test item imagePIAT test item image