ALSPAC - Age 8.5 - Wechsler Intelligence Scale for Children (WISC-III) Digital Symbol Coding

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 Digital Symbol Coding 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:	Non-verbal sequencing
Measures:	Visual-motor coordination/speed
	Short-term visual memory
	Cognitive flexibility
	Visual sequencing
	Concentration
CHC:	Gv (Visual Processing)
	Gs (Processing Speed)
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; pen and paper
Procedure:	The child was shown a key which contained geometric shapes, each of which was marked by a symbol. Next they were presented with rows and columns containing only the geometric shapes, and were tasked with marking each one with the appropriate symbol. Sample items were administered first.
	Duration: The actual trial lasted for 120 seconds.
Link to questionnaire:	http://www.bristol.ac.uk/alspac/researchers/our-data/clinical-measures/ (opens in new tab)
Scoring:	One point was awarded for each correctly drawn symbol, and these were converted to standardised scores (M = 10, SD = 3) using the WISC manual.
Item-level variable(s):	Not readily available
Total score/derived variable(s):	f8ws027 – f8ws057 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 = 7,403
	Range = 0 – 99	Range = 1 – 19
	Mean = 34.52	Mean = 10.49
	SD = 7.45	SD = 3.04
	(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:	None
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.