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

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 Similarities 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 ability
Measures:	Verbal comprehension
	Verbal reasoning
	Language development
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; oral answers
Procedure:	The interviewer asked the child whether they knew how two different things or concepts were related, e.g. “In what way are hope and fear alike?”.
Link to questionnaire:	http://www.bristol.ac.uk/alspac/researchers/our-data/clinical-measures/ (opens in new tab)
Scoring:	Items 1-5 were worth one point each, with the remaining items worth 0 – 2 points. 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):	f8ws021 – f8ws051 Explore these variables in CLOSER Discovery: ALSPAC Focus at 8 Clinic Dataset (opens in a new tab)
Descriptives:	Raw score	Scaled score
	N = 7,404	N = 7,409
	Range = 0 – 33	Range = 1 – 19
	Mean = 13.86	Mean = 12.32
	SD = 4.91	SD = 3.99
	(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 49 months – WPPSI-RUK Similarities (both verbal and picture similarities)
	BCS70 – Age 10 – BAS Word Similarities
	MCS – Age 11 – BAS II Verbal Similarities
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.
	Northstone, K., Joinson, C., Emmett, P., Ness, A., & Paus, T. (2012). Are dietary patterns in childhood associated with IQ at 8 years of age? A population-based cohort study. Journal of Epidemiology and Community Health, 66(7), 624-628.

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.