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BMC Med Inform Decis Mak. 2018 Jun 20;18(1):40. doi: 10.1186/s12911-018-0618-6.

Use of feedback to improve mental number line representations in primary care clinics.

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Department of Pharmacy Practice, University of Connecticut School of Pharmacy, 69 North Eagleville Road, Storrs, CT, 06269, USA.
Department of Psychology, Boston College, 300 McGuinn Hall, 140 Commonwealth Ave, Chestnut Hill, MA, 02467, USA.
Department of Chronic Disease Epidemiology, Yale School of Public Health, 60 College Street, New Haven, CT, 06510, USA.
Department of Medicine, Section of Rheumatology, Yale University School of Medicine, 300 Cedar Street, TAC #525, New Haven, CT, 06520, USA.
VA Connecticut Healthcare System, West Haven, CT, 06516, USA.



As patients become more engaged in decisions regarding their medical care, they must weigh the potential benefits and harms of different treatments. Patients who are low in numeracy may be at a disadvantage when making these decisions, as low numeracy is correlated with less precise representations of numerical magnitude. The current study looks at the feasibility of improving number representations. The aim of this study was to evaluate whether providing a small amount of feedback to adult subjects could improve performance on a number line placement task and to determine characteristics of those individuals who respond best to this feedback.


Subjects from two outpatient clinic waiting rooms participated in a three phase number line task. Participants were asked to place numbers on a computerized number line ranging from 0 to 1000 in pre-test, feedback, and post-test phases. Generalized estimating equations were used to model log-transformed scores and to test whether 1) performance improved after feedback, and 2) the degree of improvement was associated with age, education level or subjective numeracy.


There was an overall improvement in task performance following the feedback. The average percent absolute error was 7.32% (SD: 6.00) for the pre-test and 5.63% (SD: 3.71) for the post-test. There was a significant interaction between college education and post-test improvement. Only subjects without some college education improved with feedback.


Adults who do not have higher levels of education improve significantly on a number line task when given feedback.


Calibration; Mental number line; Numeracy

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