BCS70 – Age 46-47 – Timed Letter Search/Letter Cancellation Test

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The 1970 British Cohort Study (BCS70) assessed their cohort members (CMs) during the study’s age 46-47 sweep using the Timed Letter Search/Letter Cancellation Test.

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


DomainProcessing speed
Measures:Attention/concentration
Mental speed
Visual scanning
CHC:Gv (Visual Processing)
Gs (Processing Speed)
Administration method:Pen and paper
Procedure:Cohort members were given a page of random letters arranged in rows (N = 26) and columns (N = 30) and were asked to cross out as many "Ps" and "Ws" as possible within a one-minute timeframe. They were instructed to work across each row from left-to right as if they were reading a page and they were asked to perform the task as quickly and accurately as possible. Once the allotted time was over, the respondent was asked to underline the last letter that reached their eye (any letter, target or otherwise). The total number of letters searched was summed to provide a measure of speed of processing, whereas the total number of target letters missed reflects level of accuracy.
Link to questionnaire:https://cls.ucl.ac.uk/wp-content/uploads/2018/10/BCS70_collated-CAPI-specs_FINAL.pdf (opens in new tab)
Scoring:Speed of processing: summed total of letters scanned.
Accuracy: summed total of target letters missed.
Item-level variable(s):Not currently available
Total score/derived variable(s):B10CFCOR, B10CFMIS, B10CFRC
Descriptives:Processing speed (letter reached; raw score)Processing accuracy (number of "Ws" and "Ps" missed; raw score)
N = 8,242N = 8,242
Range = 28 - 780Range = 0 - 50
Mean = 346.45Mean = 4.26
SD = 84.78SD = 4.01
(click image to enlarge)
(click image to enlarge)
Age of participants (months):Mean = 563.26, SD = 8.26, Range = 542 - 578
Other sweep and/or cohort:NCDS – Age 50 – Timed Letter Search/Letter Cancellation Test
NCDS – Age 61-63 – Proposed repeat of tests at age 50
NSHD – Age 43 – Timed Letter Search/Letter Cancellation Test (3 trials)
NSHD – Age 53 – Timed Letter Search/Letter Cancellation Test
NSHD – Age 60-64 – Timed Letter Search/Letter Cancellation Test
NSHD – Age 68-70 – Timed Letter Search/Letter Cancellation Test
Source:The letter cancellation test was initially developed for the NSHD 1946 birth cohort study (Richards et al., 1999) and has also been used in the MRC Cognitive Function and Ageing Study (MRC CFA Study, 1998). All cognitive measures at this sweep were taken from the 2002 English Longitudinal Study of Ageing (ELSA; Taylor et al., 2007).
Technical resources:Banks, J., Breeze, E., Lessof, C., & Nazroo, J. (2006). Retirement, health and relationships of the older population in England: The 2004 English Longitudinal Study of Ageing (Wave 2).
Reference examples:Not available at time of writing

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This page is part of CLOSER’s ‘A guide to the cognitive measures in five British birth cohort studies’.