List of variables described on this page
Click on a variable name in the table below to go to the description on this page. Alternatively, scroll down and find variables in alphabetical order.
Definitions of derived variables
Listed alphabetically
hage
Age of the twins (in decimal years) when the 8yr questionnaire was completed.
Derived from the date of completion of the questionnaire if available; or from
the logged return date if not.
Hdate (date recorded on questionnaire) and hretdate (date of return of
questionnaire to the TEDS office) and aonsdob (twin birthdate) are temporary
date variables that are not retained in the dataset.
* Calculate age of twins when 8yr questionnaire completed/returned. * Dates scanned from paper (hdate) are prone to typos and scanning errors. * so use the logged return date (hretdate) out of preference. COMPUTE tempdate = hretdate. EXECUTE. * in a few cases where this is missing, use the qnr date. IF (SYSMIS(hretdate)) tempdate = hdate. EXECUTE. * Subtract birthdate to derive age. COMPUTE hage = RND(((DATEDIFF(tempdate, aonsdob, "days")) / 365.25), 0.1). EXECUTE.
hcacomt1/2
CAST Communication scale.
Derived from 12 of the CAST items, using reversed versions where appropriate,
and requiring at least 6 of the 12 items to be present. Each item has values
0/1, hence this scale has values 0 to 12.
* Cast Communication scale. * Require at least 6 out of 12 items. COMPUTE hcacomt1 = 12 * MEAN.6(hca10r1,hca11r1,hca17r1,hca23r1, hca071,hca181,hca201,hca251,hca301,hca321,hca361,hca371). COMPUTE hcacomt2 = 12 * MEAN.6(hca10r2,hca11r2,hca17r2,hca23r2, hca072,hca182,hca202,hca252,hca302,hca322,hca362,hca372). EXECUTE.
hcanont1/2
CAST Non-social scale.
Derived from 7 of the CAST items, using reversed versions where appropriate, and
requiring at least 5 of the 7 items to be present. Each item has values 0/1,
hence this scale has values 0 to 7.
* Cast Non-social scale. * Require at least 4 out of 7 items. COMPUTE hcanont1 = 7 * MEAN.4(hca13r1,hca061,hca091,hca141,hca191,hca281,hca341). COMPUTE hcanont2 = 7 * MEAN.4(hca13r2,hca062,hca092,hca142,hca192,hca282,hca342). EXECUTE.
hcasoct1/2
CAST Social scale.
Derived from 12 of the CAST items, using reversed versions where appropriate,
and requiring at least 6 of the 12 items to be present. Each item has values
0/1, hence this scale has values 0 to 12.
* Cast Social scale. * Require at least 6 out of 12 items. COMPUTE hcasoct1 = 12 * MEAN.6(hca01r1,hca02r1,hca05r1,hca08r1,hca15r1, hca16r1,hca21r1,hca24r1,hca27r1,hca31r1,hca35r1,hca291). COMPUTE hcasoct2 = 12 * MEAN.6(hca01r2,hca02r2,hca05r2,hca08r2,hca15r2, hca16r2,hca21r2,hca24r2,hca27r2,hca31r2,hca35r2,hca292). EXECUTE.
hcastt1/2
CAST overall Total scale.
Derived from 31 of the CAST items, using reversed versions where appropriate,
and requiring at least 16 of the 31 items to be present. Each item has values
0/1, hence this scale has values 0 to 31.
* Cast Total scale. * Sum of 31 Cast items, each scored 0 or 1 (exclude the 6 control questions). * Derive as a re-scaled mean, with total values in range 0 to 31. * Use reversed versions of 16 items, other 15 items are non-reversed. * Scale requires at least 16 of the items to be non-missing. COMPUTE hcastt1 = 31 * MEAN.16(hca01r1,hca02r1,hca05r1,hca08r1,hca10r1,hca11r1,hca13r1,hca15r1, hca16r1,hca17r1,hca21r1,hca23r1,hca24r1,hca27r1,hca31r1,hca35r1, hca061,hca071,hca091,hca141,hca181,hca191,hca201,hca251, hca281,hca291,hca301,hca321,hca341,hca361,hca371). COMPUTE hcastt2 = 31 * MEAN.16(hca01r2,hca02r2,hca05r2,hca08r2,hca10r2,hca11r2,hca13r2,hca15r2, hca16r2,hca17r2,hca21r2,hca23r2,hca24r2,hca27r2,hca31r2,hca35r2, hca062,hca072,hca092,hca142,hca182,hca192,hca202,hca252, hca282,hca292,hca302,hca322,hca342,hca362,hca372). EXECUTE.
hconhit1/2
Conners Hyperactivity-Impulsivity scale.
Derived from 9 of the 18 Conners items, requiring at least 5 of the items to be
non-missing. Each item has values 0-3, hence the scale has values 0 to 27.
* Hyperactivity-Impulsivity combined scale. * From 9 of the 18 Conners items, each having values between 0 and 3. COMPUTE hconhit1 = 9 * MEAN.5(hcon011,hcon051,hcon081,hcon101, hcon111,hcon131,hcon141,hcon161,hcon181). COMPUTE hconhit2 = 9 * MEAN.5(hcon012,hcon052,hcon082,hcon102, hcon112,hcon132,hcon142,hcon162,hcon182). EXECUTE .
hconint1/2
Conners Inattention scale.
Derived from 9 of the 18 Conners items, requiring at least 5 of the items to be
non-missing. Each item has values 0-3, hence the scale has values 0 to 27.
* Inattention scale. * From the other 9 of the 18 Conners items, each having values between 0 and 3. COMPUTE hconint1 = 9 * MEAN.5(hcon021,hcon031,hcon041,hcon061, hcon071,hcon091,hcon121,hcon151,hcon171). COMPUTE hconint2 = 9 * MEAN.5(hcon022,hcon032,hcon042,hcon062, hcon072,hcon092,hcon122,hcon152,hcon172). EXECUTE .
hconnt1/2
Conners overall Total scale.
Derived from all 18 Conners items, requiring at least 9 of the items to be
non-missing. Each item has values 0-3, hence the scale has values 0 to 54.
* Conners Total scale. * Sum of all 18 Conners items, each scored 0 to 3. * Creating total (0-54). * Scale requires at least 9 of the 18 items to be non-missing. COMPUTE hconnt1 = 18 * MEAN.9(hcon011,hcon021,hcon031,hcon041,hcon051,hcon061, hcon071,hcon081,hcon091,hcon101,hcon111,hcon121, hcon131,hcon141,hcon151,hcon161,hcon171,hcon181). COMPUTE hconnt2 = 18 * MEAN.9(hcon012,hcon022,hcon032,hcon042,hcon052,hcon062, hcon072,hcon082,hcon092,hcon102,hcon112,hcon122, hcon132,hcon142,hcon152,hcon162,hcon172,hcon182). EXECUTE.
hLLCage, hLLCdate
Age and date variables derived for use in datasets in the LLC TRE (but
not to be used in other datasets).
The LLC date variable contains only the month and year, not the day, as a means of
reducing identifiability. The date variable values are strings formatted as 'yyyy-mm'.
These LLC dates are designed to enable the TEDS measures to be placed in a time
sequence with NHS medical diagnosis dates in the data in the TRE.
The LLC age variables are integers measuring the number of months between birth and
the given TEDS activity, consistent with the matching LLC date variables.
Variable aonsdob is the twin birth date, and tempdate is the best estimate
of the questionnaire date - these raw date variables are not
retained in the dataset.
* LLC date and age variables. * Use these only as file 2 variables for the LLC TRE, do not use in other researcher datasets. * First extract year and month as temp variables, from birth date and activity dates. COMPUTE birthyear = XDATE.YEAR(aonsdob). COMPUTE birthmonth = XDATE.MONTH(aonsdob). COMPUTE hyear = XDATE.YEAR(tempdate). COMPUTE hmonth = XDATE.MONTH(tempdate). EXECUTE. * The agreed LLC date format is a string yyyy-mm (nominal by default for strings). * adding '0' where necessary for two-digit months. STRING hLLCdate (A7). IF (hmonth < 10) hLLCdate = CONCAT(STRING(hyear, F4), '-0', STRING(hmonth, F1)). IF (hmonth >= 10) hLLCdate = CONCAT(STRING(hyear, F4), '-', STRING(hmonth, F2)). EXECUTE. * The agreed LLC age variable is in integer months. * and it must agree with the birth and booklet year/month variables that will be available in the LLC. COMPUTE hLLCage = (hmonth + (hyear * 12)) - (birthmonth + (birthyear * 12)). EXECUTE.
hrpqt1/2
RPQ Total scale.
Derived from all 18 RPQ items, requiring at least 9 of them to be non-missing.
Each item has values 0 to 3, hence the scale has values 0 to 54.
* RPQ Total scale. * Sum of all 18 RPQ items, each scored 0 to 3. * Creating total (0-54). * Scale requires at least 9 of the items to be non-missing. COMPUTE hrpqt1 = 18 * MEAN.9(hrpq011,hrpq021,hrpq031,hrpq041,hrpq051,hrpq061, hrpq071,hrpq081,hrpq091,hrpq101,hrpq111,hrpq121, hrpq131,hrpq141,hrpq151,hrpq161,hrpq171,hrpq181). COMPUTE hrpqt2 = 18 * MEAN.9(hrpq012,hrpq022,hrpq032,hrpq042,hrpq052,hrpq062, hrpq072,hrpq082,hrpq092,hrpq102,hrpq112,hrpq122, hrpq132,hrpq142,hrpq152,hrpq162,hrpq172,hrpq182). EXECUTE.