ALSPAC – Age 8.5 – Wechsler Intelligence Scale for Children (WISC-III) Comprehension

The Avon Longitudinal Study of Parents and Children (ALSPAC) assessed their cohort members (CMs) during the study’s age 8.5 sweep (Focus@8) using the Comprehension measure from the Wechsler Intelligence Scale for Children (WISC-III).

Details on this measure and the data collected from the CMs are outlined in the table below.

Years of data collection:	1999-2001
Domain:	Verbal comprehension
Measures:	Verbal comprehension
	Verbal reasoning
	Verbal expression
CHC:	Gc (Crystallised intelligence)
CLOSER Source:	Explore this sweep in CLOSER Discovery: ALSPAC Childhood (5 years to 12 years 11 months) (opens in a new tab)
Administration method:	Trained interviewer; clinical setting; child answers orally
Procedure:	The child was asked a series of questions based on his or her understanding of general concepts, e.g. “Why do people brush their teeth?”, “Why can birds fly, but cats can’t?”. Interviewers were allowed to repeat questions if the child did not understand. Responses were scored on a 0 – 2 metric. If the child spontaneously improved their answer, this was accepted.
Link to questionnaire:	http://www.bristol.ac.uk/alspac/researchers/our-data/clinical-measures/ (opens in new tab)
Scoring:	Responses were scored on a 0 – 2 metric. Raw scores were converted into scale scores using tables provided in the WISC manual (M = 10, SD = 3).
Item-level variable(s):	Not readily available
Total score/derived variable(s):	f8ws024 – f8ws054 Explore these variables in CLOSER Discovery: ALSPAC Focus at 8 Clinic Dataset (opens in a new tab)
Descriptives:	Raw score	Scaled score
	N = 7,328	N = 7,334
	Range = 0 – 34	Range = 1 – 19
	Mean = 17.13	Mean = 10.98
	SD = 4.77	SD = 3.71
	(click image to enlarge)	(click image to enlarge)
Age of participants (months):	Mean = 103.82 months, SD = 3.92, Range = 89 – 127
Other sweep and/or cohort:	ALSPAC – Age 4 – WPPSI-RUK Comprehension
Source:	Wechsler, D. (1991). WISC-III: Wechsler intelligence scale for children: Manual. Psychological Corporation.
Technical resources:	Kaufman, A. S., & Lichtenberger, E. O. (2000). Essentials of WISC-III and WPPSI-R assessment. John Wiley & Sons Inc.
Example articles:	Horwood, J., Salvi, G., Thomas, K., Duffy, L., Gunnell, D., Hollis, C., … & Zammit, S. (2008). IQ and non-clinical psychotic symptoms in 12-year-olds: results from the ALSPAC birth cohort. The British Journal of Psychiatry, 193(3), 185-191.
	Bornstein, M. H., Hahn, C. S., & Wolke, D. (2013). Systems and cascades in cognitive development and academic achievement. Child Development, 84(1), 154-162.

For the named items in the table above, links are provided to their corresponding content on CLOSER Discovery. Where a variable range is provided, full variable lists can be accessed through the ‘Variable Groups’ tab on the linked Discovery page.