TEDS Data Dictionary

Variables in the 2 Year Dataset

The table on this page lists all 2 Year variables. This includes all item variables from the 2 Year booklets, as well as derived variables that are based on 2 Year items.

The table does not include background variables that originate from other sources (either from admin data or from other study datasets). Such variables include IDs, twin sex and zygosity variables, the random variable and general exclusion variables. See the background variables page for details.

Variables are listed in alphabetical order in the table below. The columns of the table are:

Dataset variable name
Dataset variable label (in SPSS)
Source of data:
- child - from the child booklet
- parent - from the parent booklet
Item or derived variable? - see item coding for the parent and child booklets (pdfs) for item variables; see also the description of derived variables for more information.
Data type:
- integer - numeric whole numbers
- decimal - numeric with fractional values
Variable type:
- nominal - categorical, with arbitrary numeric values
- ordinal - categorical, with ordered numeric values (test items used as scores are treated as being ordinal even if they have a simple 0/1 coding)
- quantitative - numerical measurements of some concrete quantity such as length of time
- scale value - numerical measurement derived (usually) as a sum or mean of other variables
Coding or range of values - this shows the value coding used for nominal/ordinal variables, or an approximate range of values for quantitative and scale variables.

dataset variable name	dataset variable label	source of data	item or derived variable?	data type	variable level	coding or approximate range of values
badparc1/2	Parent-administered Parca total score (2 Year), 0-34	child	derived	integer	scale value	0 to 34
badparn1/2	Parent-administered Parca mean score (2 Year), standardised	child	derived	decimal	scale value	approx. -3 to +3 (standardised)
bagemdex	Exclude on moderate twin age rules (2 Year), 1Y 0N	child	derived	integer	nominal	0=no, 1=yes
bagestex	Exclude on strict twin age rules (2 Year), 1Y 0N	child	derived	integer	nominal	0=no, 1=yes
bbeh011/2	2 Year behaviour item 2 (Behar item 1): fair in games, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh021/2	2 Year behaviour item 3 (Behar item 2): restless, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh031/2	2 Year behaviour item 4 (Behar item 3): considerate, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh041/2	2 Year behaviour item 5 (Behar item 4): fidgety, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh051/2	2 Year behaviour item 6 (Behar item 5): destroys belongings, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh061/2	2 Year behaviour item 7 (Behar item 6): affectionate to family, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh071/2	2 Year behaviour item 8 (Behar item 7): fights, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh081/2	2 Year behaviour item 9 (Behar item 8): not much liked, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh091/2	2 Year behaviour item 10 (Behar item 9): helps around house, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh101/2	2 Year behaviour item 11 (Behar item 10): worried, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh111/2	2 Year behaviour item 12 (Behar item 11): solitary, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh121/2	2 Year behaviour item 13 (Behar item 12): irritable, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh131/2	2 Year behaviour item 14 (Behar item 13): helps someone if hurt, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh141/2	2 Year behaviour item 15 (Behar item 14): appears miserable, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh151/2	2 Year behaviour item 16 (Behar item 15): has twitches, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh161/2	2 Year behaviour item 17 (Behar item 16): bites nails, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh171/2	2 Year behaviour item 18 (Behar item 17): disobedient, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh181/2	2 Year behaviour item 19 (Behar item 18): kind to younger children, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh191/2	2 Year behaviour item 20 (Behar item 19): poor concentration, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh201/2	2 Year behaviour item 21 (Behar item 20): afraid of new things, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh211/2	2 Year behaviour item 22 (Behar item 21): helps ill children, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh221/2	2 Year behaviour item 23 (Behar item 22): fussy, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh231/2	2 Year behaviour item 24 (Behar item 23): tells lies, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh241/2	2 Year behaviour item 25 (Behar item 24): wet self, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh251/2	2 Year behaviour item 26 (Behar item 25): comforts upset children, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh261/2	2 Year behaviour item 27 (Behar item 26): stutters, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh271/2	2 Year behaviour item 28 (Behar item 27): speech difficulty, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh281/2	2 Year behaviour item 29 (Behar item 28): plays imaginatively, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh291/2	2 Year behaviour item 30 (Behar item 29): bullies, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh301/2	2 Year behaviour item 31 (Behar item 30): inattentive, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh311/2	2 Year behaviour item 32 (Behar item 31): gets on well, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh31r1/2	Reversed version of 2 Year behaviour item 32 (Behar item 31), see value labels	child	item	integer	ordinal	2=not true, 1=sometimes true, 0=certainly true
bbeh321/2	2 Year behaviour item 33 (Behar item 32): does not share toys, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh331/2	2 Year behaviour item 34 (Behar item 33): cries easily, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh341/2	2 Year behaviour item 35 (Behar item 34): forceful, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh351/2	2 Year behaviour item 36 (Behar item 35): blames others, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh361/2	2 Year behaviour item 37 (Behar item 36): shares treats, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh371/2	2 Year behaviour item 38 (Behar item 37): gives up easily, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh381/2	2 Year behaviour item 39 (Behar item 38): inconsiderate, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh391/2	2 Year behaviour item 40 (Behar item 39): independent, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh39r1/2	Reversed version of 2 Year behaviour item 40 (Behar item 39), see value labels	child	item	integer	ordinal	2=not true, 1=sometimes true, 0=certainly true
bbeh401/2	2 Year behaviour item 41 (Behar item 40): kicks and bites, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh411/2	2 Year behaviour item 42 (Behar item 41): kind to animals, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh421/2	2 Year behaviour item 43 (Behar item 42): stares into space, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbeh431/2	2 Year behaviour item 44 (Behar item 43): stops fights, see value labels	child	item	integer	ordinal	0=not true, 1=sometimes true, 2=certainly true
bbh011/2	2 Year behaviour item 1: spend time with other children, see value labels	child	item	integer	ordinal	0=never, 1=occasionally, 2=sometimes, 3=often
bblockt1/2	Block test total score (2 Year), 0-12	child	derived	integer	scale value	0 to 12
bchjob	Respondent job changed (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
bchpartn	Partner changed (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
bchpjob	Partner job changed (2 Year), see value labels	parent	item	integer	nominal	0=no, 1=yes, 2=do not have a partner
bchstatus	Marital status changed (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
bcomplx1/2	Sentence Complexity total score (2 Year), 0-13	child	derived	integer	scale value	0 to 13
bcont1/2	Overall Behar Conduct problems scale (2 Year), 0-18	child	derived	decimal	scale value	0 to 18
bcopyt1/2	Copy test total score (2 Year), 0-8	child	derived	integer	scale value	0 to 8
bdrawt1/2	Drawing test total score (2 Year), 0-4	child	derived	integer	scale value	0 to 4
bemot1/2	Overall Behar Emotion problems scale (2 Year), 0-10	child	derived	decimal	scale value	0 to 10
bexcludm	General exclusion combined with moderate twin age rules (2 Year), 1Y 0N	child	derived	integer	nominal	0=no, 1=yes
bexcluds	General exclusion combined with strict twin age rules (2 Year), 1Y 0N	child	derived	integer	nominal	0=no, 1=yes
bfahosp	Father hospital stay necessary (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
bfasick	Father has had serious illness (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
bfasickd	Length of father illness in days (2 Year), see value labels	parent	item	integer	ordinal	1=1 day, 2=2 or more days
bfoldt1/2	Paper Folding test total score (2 Year), 0-2	child	derived	integer	scale value	0 to 2
bgramma1/2	Grammar composite score (2 Year), 0-2	child	derived	integer	ordinal	0 to 2
bhypt1/2	Overall Behar Hyperactivity problems scale (2 Year), 0-10	child	derived	decimal	scale value	0 to 10
bmatcht1/2	Matching test total score (2 Year), 0-8	child	derived	integer	scale value	0 to 8
bmohosp	Mother hospital stay necessary (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
bmosick	Mother has had serious illness (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
bmosickd	Length of mother illness in days (2 Year), see value labels	parent	item	integer	ordinal	1=1 day, 2=2 or more days
bmstatus	Respondent marital status (2 Year), see value labels	parent	derived	integer	nominal	1=married to parent of twins, 2=married to someone else, 3=cohabiting with parent of twins, 4=cohabiting with someone else, 5=divorced, 6=separated, 7=widowed, 8=unmarried
bnewchld	New children living at home (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
bparca1/2	Parca overall mean score (2 Year), standardised	child	derived	decimal	scale value	approx. -3 to +3 (standardised)
bparent	Parent booklet data present (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
bpb01a1/2	Block test item 1a: number of bricks in row (2 Year), 0-10	child	item	integer	quantitative	0 to 10 (number of bricks)
bpb01b1/2	Block test item 1b: can push row of bricks (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpb01s1/2	Block test item 1 score (2 Year), 0-3	child	derived	integer	ordinal	0 to 3
bpb021/2	Block test item 2: number of bricks in tower (2 Year), 0-10	child	item	integer	quantitative	0 to 10 (number of bricks)
bpb02s1/2	Block test item 2 score (2 Year), 0-3	child	derived	integer	ordinal	0 to 3
bpb03a1/2	Block test item 3a: two bricks at bottom of bridge (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpb03b1/2	Block test item 3b: one brick on top of bridge (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpb03c1/2	Block test item 3c: top brick touches bottom bricks (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpb03s1/2	Block test item 3 score (2 Year), 0-3	child	derived	integer	ordinal	0 to 3
bpb04a1/2	Block test item 4a: two rows of bricks in wall (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpb04b1/2	Block test item 4b: two bricks at bottom of wall (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpb04c1/2	Block test item 4c: two bricks at top of wall (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpb04s1/2	Block test item 4 score (2 Year), 0-3	child	derived	integer	ordinal	0 to 3
bpbage	Twin age in years on completion of parent booklet (2 Year)	parent	derived	decimal	quantitative	approx. 1.8 to 3 years
bpbLLCage	Age of twin when 2 year parent booklet completed (for use in LLC TRE), months	parent	derived	integer	quantitative	approx. 22 to 36 (months)
bpbLLCdate	Date when 2 year parent booklet completed (for use in LLC TRE), yyyy-mm string	parent	derived	string	date value	approx. '1996-01' to '1998-01'
bpc011/2	Copy test item 1: open and close mouth (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpc01s1/2	Copy test items 1-4 total score (2 Year), 0-2	child	derived	integer	ordinal	0 to 2
bpc021/2	Copy test item 2: pull earlobe (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpc031/2	Copy test item 3: blink eyes (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpc041/2	Copy test item 4: pat cheek (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpc05a1/2	Copy test item 5a: copies two actions (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpc05b1/2	Copy test item 5b: two actions in correct order (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpc05s1/2	Copy test item 5 score (2 Year), 0-2	child	derived	integer	ordinal	0 to 2
bpc06a1/2	Copy test item 6a: copies three actions (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpc06b1/2	Copy test item 6b: three actions in correct order (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpc06s1/2	Copy test item 6 score (2 Year), 0-2	child	derived	integer	ordinal	0 to 2
bpc07a1/2	Copy test item 7a: copies four actions (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpc07b1/2	Copy test item 7b: four actions in correct order (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpc07s1/2	Copy test item 7 score (2 Year), 0-2	child	derived	integer	ordinal	0 to 2
bpd011/2	Drawing item 1 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpd021/2	Drawing item 2 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpd031/2	Drawing item 3 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpd041/2	Drawing item 4 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpm01s1/2	Matching item 1 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes
bpm02s1/2	Matching item 2 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes
bpm03s1/2	Matching item 3 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes
bpm04s1/2	Matching item 4 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes
bpm05s1/2	Matching item 5 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes
bpm06s1/2	Matching item 6 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes
bpm07s1/2	Matching item 7 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes
bpm08s1/2	Matching item 8 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes
bpp01a1/2	Paper Folding test item 1a: tries to fold paper (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpp01b1/2	Paper Folding test item 1b: makes just one fold (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr011/2	Parent-Reported Parca item 1: piece in puzzle (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr021/2	Parent-Reported Parca item 2: shapes in openings (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr031/2	Parent-Reported Parca item 3: stack three blocks (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr041/2	Parent-Reported Parca item 4: stack seven blocks (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr051/2	Parent-Reported Parca item 5: jigsaw (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr061/2	Parent-Reported Parca item 6: jigsaw with ten pieces (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr071/2	Parent-Reported Parca item 7: mark on paper (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr081/2	Parent-Reported Parca item 8: draw line (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr091/2	Parent-Reported Parca item 9: turn pages (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr101/2	Parent-Reported Parca item 10: pretend objects (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr111/2	Parent-Reported Parca item 11: pretend actions (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr121/2	Parent-Reported Parca item 12: pretend dolls (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr131/2	Parent-Reported Parca item 13: pretend games (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr141/2	Parent-Reported Parca item 14: taking turns (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr151/2	Parent-Reported Parca item 15: copy actions (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr161/2	Parent-Reported Parca item 16: fetch objects (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr171/2	Parent-Reported Parca item 17: know where things belong (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr181/2	Parent-Reported Parca item 18: put aside snacks (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr191/2	Parent-Reported Parca item 19: gather toys (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr201/2	Parent-Reported Parca item 20: put things in groups (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr211/2	Parent-Reported Parca item 21: find chair to stand on (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr221/2	Parent-Reported Parca item 22: speak into phone (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr231/2	Parent-Reported Parca item 23: avoids spilling drinks (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr241/2	Parent-Reported Parca item 24: turns doorknobs (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr251/2	Parent-Reported Parca item 25: recognise reflection (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpr261/2	Parent-Reported Parca item 26: points (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bpreg	Mother of twins pregnant (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
bprot1/2	Overall Behar Prosocial problems scale (2 Year), 0-20	child	derived	decimal	scale value	0 to 20
brawg1/2	G: overall cognitive ability composite (2 Year), standardised	child	derived	decimal	scale value	approx. -3 to +3 (standardised)
breparc1/2	Parent-reported Parca total score (2 Year), 0-26	child	derived	integer	scale value	0 to 26
bs01s1/2	Sentence Complexity item 1 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bs02s1/2	Sentence Complexity item 2 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bs03s1/2	Sentence Complexity item 3 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bs04s1/2	Sentence Complexity item 4 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bs05s1/2	Sentence Complexity item 5 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bs06s1/2	Sentence Complexity item 6 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bs07s1/2	Sentence Complexity item 7 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bs08s1/2	Sentence Complexity item 8 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bs09s1/2	Sentence Complexity item 9 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bs10s1/2	Sentence Complexity item 10 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bs11s1/2	Sentence Complexity item 11 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bs12s1/2	Sentence Complexity item 12 correct score (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bscnv1/2	Non-verbal cognitive ability composite (2 Year), standardised	child	derived	decimal	scale value	approx. -3 to +3 (standardised)
bscv1/2	Verbal cognitive ability composite (2 Year), standardised	child	derived	decimal	scale value	approx. -2 to +2 (standardised)
bsdqcbeht1/2	Total behaviour problems: SDQ-comparable Behar scale (2 Year), 0-24	child	derived	decimal	scale value	0 to 24
bsdqccont1/2	Conduct SDQ-comparable Behar subscale (2 Year), 0-8	child	derived	decimal	scale value	0 to 8
bsdqcemot1/2	Emotion SDQ-comparable Behar subscale (2 Year), 0-4	child	derived	decimal	scale value	0 to 4
bsdqchypt1/2	Hyperactivity SDQ-comparable Behar subscale (2 Year), 0-6	child	derived	decimal	scale value	0 to 6
bsdqcpert1/2	Peer problem SDQ-comparable Behar subscale (2 Year), 0-6	child	derived	decimal	scale value	0 to 6
bsdqcprot1/2	Prosocial SDQ-comparable Behar subscale (2 Year), 0-10	child	derived	decimal	scale value	0 to 10
bsibhosp	Sibling hospital stay necessary (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
bsibsicd	Length of sibling illness in days (2 Year), see value labels	parent	item	integer	ordinal	1=1 day, 2=2 or more days
bsibsick	Sibling has had serious illness (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
btwbage1/2	Twin age in years on completion of the twin booklet (2 Year)	child	derived	decimal	quantitative	approx. 1.8 to 3 years
btwbagediff	Difference in twin ages on completion of the child booklet (2 Year), years	child	derived	decimal	quantitative	approx. 0 to 0.8 year
btwbLLCage1	Age of twin when 2 year twin booklet completed (for use in LLC TRE), months	child	derived	integer	quantitative	approx. 23 to 34 (months)
btwbLLCdate1	Date when 2 year twin booklet completed (for use in LLC TRE), yyyy-mm string	child	derived	string	date value	approx. '1996-01' to '1998-01'
btwdata1/2	Twin booklet data present (2 Year), 1Y 0N	child	item	integer	nominal	0=no, 1=yes
btwhosp1/2	Twin hospital stay necessary (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
btwoyear	2 Year data present, 1Y 0N	parent and child	derived	integer	nominal	0=no, 1=yes
btwsicd1/2	Length of twin illness in days (2 Year), see value labels	parent	item	integer	ordinal	1=1 day, 2=2-7 days, 3=8-14 days, 4=15 or more days
btwsick1/2	Twin has had serious illness (2 Year), 1Y 0N	parent	item	integer	nominal	0=no, 1=yes
buse1/2	Word use total score (2 Year), 0-5	child	derived	integer	scale value	0 to 5
bvc0011/2	Vocabulary item 1: can say baa baa (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0021/2	Vocabulary item 2: can say hat (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0031/2	Vocabulary item 3: can say sky (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0041/2	Vocabulary item 4: can say allgone (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0051/2	Vocabulary item 5: can say meow (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0061/2	Vocabulary item 6: can say necklace (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0071/2	Vocabulary item 7: can say zoo (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0081/2	Vocabulary item 8: can say cold (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0091/2	Vocabulary item 9: can say ouch (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0101/2	Vocabulary item 10: can say shoe (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0111/2	Vocabulary item 11: can say friend (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0121/2	Vocabulary item 12: can say fast (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0131/2	Vocabulary item 13: can say oh dear (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0141/2	Vocabulary item 14: can say sock (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0151/2	Vocabulary item 15: can say mummy (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0161/2	Vocabulary item 16: can say happy (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0171/2	Vocabulary item 17: can say woof woof (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0181/2	Vocabulary item 18: can say chin (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0191/2	Vocabulary item 19: can say person (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0201/2	Vocabulary item 20: can say hot (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0211/2	Vocabulary item 21: can say bear (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0221/2	Vocabulary item 22: can say ear (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0231/2	Vocabulary item 23: can say byebye (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0241/2	Vocabulary item 24: can say last (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0251/2	Vocabulary item 25: can say bird (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0261/2	Vocabulary item 26: can say hand (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0271/2	Vocabulary item 27: can say hello (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0281/2	Vocabulary item 28: can say tiny (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0291/2	Vocabulary item 29: can say cat (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0301/2	Vocabulary item 30: can say leg (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0311/2	Vocabulary item 31: can say no (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0321/2	Vocabulary item 32: can say wet (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0331/2	Vocabulary item 33: can say dog (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0341/2	Vocabulary item 34: can say pillow (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0351/2	Vocabulary item 35: can say shopping (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0361/2	Vocabulary item 36: can say after (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0371/2	Vocabulary item 37: can say duck (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0381/2	Vocabulary item 38: can say comb (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0391/2	Vocabulary item 39: can say thank you (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0401/2	Vocabulary item 40: can say day (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0411/2	Vocabulary item 41: can say horse (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0421/2	Vocabulary item 42: can say lamp (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0431/2	Vocabulary item 43: can say carry (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0441/2	Vocabulary item 44: can say tonight (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0451/2	Vocabulary item 45: can say aeroplane (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0461/2	Vocabulary item 46: can say plate (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0471/2	Vocabulary item 47: can say chase (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0481/2	Vocabulary item 48: can say our (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0491/2	Vocabulary item 49: can say boat (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0501/2	Vocabulary item 50: can say rubbish (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0511/2	Vocabulary item 51: can say pour (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0521/2	Vocabulary item 52: can say them (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0531/2	Vocabulary item 53: can say car (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0541/2	Vocabulary item 54: can say tray (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0551/2	Vocabulary item 55: can say finish (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0561/2	Vocabulary item 56: can say this (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0571/2	Vocabulary item 57: can say ball (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0581/2	Vocabulary item 58: can say towel (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0591/2	Vocabulary item 59: can say fit (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0601/2	Vocabulary item 60: can say us (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0611/2	Vocabulary item 61: can say book (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0621/2	Vocabulary item 62: can say bed (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0631/2	Vocabulary item 63: can say hug (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0641/2	Vocabulary item 64: can say where (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0651/2	Vocabulary item 65: can say game (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0661/2	Vocabulary item 66: can say bedroom (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0671/2	Vocabulary item 67: can say listed (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0681/2	Vocabulary item 68: can say beside (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0691/2	Vocabulary item 69: can say sandwich (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0701/2	Vocabulary item 70: can say settee (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0711/2	Vocabulary item 71: can say like (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0721/2	Vocabulary item 72: can say down (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0731/2	Vocabulary item 73: can say fish (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0741/2	Vocabulary item 74: can say oven (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0751/2	Vocabulary item 75: can say pretend (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0761/2	Vocabulary item 76: can say under (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0771/2	Vocabulary item 77: can say sauce (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0781/2	Vocabulary item 78: can say stairs (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0791/2	Vocabulary item 79: can say rip (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0801/2	Vocabulary item 80: can say all (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0811/2	Vocabulary item 81: can say cream cracker (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0821/2	Vocabulary item 82: can say flag (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0831/2	Vocabulary item 83: can say shake (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0841/2	Vocabulary item 84: can say much (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0851/2	Vocabulary item 85: can say juice (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0861/2	Vocabulary item 86: can say rain (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0871/2	Vocabulary item 87: can say taste (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0881/2	Vocabulary item 88: can say could (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0891/2	Vocabulary item 89: can say meat (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0901/2	Vocabulary item 90: can say star (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0911/2	Vocabulary item 91: can say gentle (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0921/2	Vocabulary item 92: can say need to (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0931/2	Vocabulary item 93: can say milk (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0941/2	Vocabulary item 94: can say swing (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0951/2	Vocabulary item 95: can say think (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0961/2	Vocabulary item 96: can say would (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0971/2	Vocabulary item 97: can say peas (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0981/2	Vocabulary item 98: can say school (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc0991/2	Vocabulary item 99: can say wish (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvc1001/2	Vocabulary item 100: can say if (2 Year), 1Y 0N	child	item	integer	ordinal	0=no, 1=yes
bvocab1/2	Vocabulary total score (2 Year), 0-100	child	derived	integer	scale value	0 to 100
bwu011/2	Word use item 1 response: talk about past events (2 Year), see value labels	child	item	integer	nominal	1=often, 2=sometimes, 3=not yet
bwu01s1/2	Word use item 1 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes
bwu021/2	Word use item 2 response: talk about future (2 Year), see value labels	child	item	integer	nominal	1=often, 2=sometimes, 3=not yet
bwu02s1/2	Word use item 2 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes
bwu031/2	Word use item 3 response: talk about objects not present (2 Year), see value labels	child	item	integer	nominal	1=often, 2=sometimes, 3=not yet
bwu03s1/2	Word use item 3 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes
bwu041/2	Word use item 4 response: ask for something not in room (2 Year), see value labels	child	item	integer	nominal	1=often, 2=sometimes, 3=not yet
bwu04s1/2	Word use item 4 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes
bwu051/2	Word use item 5 response: names absent owner of object (2 Year), see value labels	child	item	integer	nominal	1=often, 2=sometimes, 3=not yet
bwu05s1/2	Word use item 5 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes
bwu061/2	Word use item 6 response: combines words (2 Year), see value labels	child	item	integer	nominal	1=often, 2=sometimes, 3=not yet
bwu06s1/2	Word use item 6 correct score (2 Year), 1Y 0N	child	derived	integer	ordinal	0=no, 1=yes