Definitions of developmental dyscalculia vary widely across studies, with diagnostic cutoffs ranging from below the 3rd to below the 25th percentile¶

Claim · All claims
Evidence · 1 study · associational r2 · q2
Currency · newest study 2013 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q2 i? There is no agreed definition of DD and cutoff variation across studies may contribute to disagreeing findings. → Szucs Denes 2013

Evidence¶

Szucs Denes 2013¶

Szucs Denes, Devine Amy, Soltesz Fruzsina, Nobes Alison, Gabriel Florence. (2013). Developmental dyscalculia is related to visuo-spatial memory and inhibition impairment. Cortex, 49(10). https://doi.org/10.1016/j.cortex.2013.06.007

q2 · i? · associational · r2

The article's review of diagnostic practice reports cutoffs "from performance below the 3rd percentile to performance below the 25th percentile" and contrasts its own stringent two-test, 1SD criteria with looser criteria in prior studies, some of which included dyslexic children.

"It is important to point out that there is substantial variation across studies in defining children with DD due to the fact that there is no agreed definition of DD."

Discussion¶

Related Claims¶

• Developmental dyscalculia prevalence was 5.6% in this UK sample, with no significant gender difference — related
• Screening assessments vary in design, administration, and risk definitions such that there is no truly common definition of risk across assessments — a broader claim this one bears on
• Different responsiveness-determination approaches (status vs. slope, criteria, domains, cut points) identify different students as adequate and inadequate responders, with little or no overlap — a broader claim this one bears on
• Screening assessment benchmarks indicating significant risk shift up and down on the MCAS scale within and across grades, so students with the same skills may be classified differently at different times — a broader claim this one bears on
• Early literacy screening assessments provide multiple benchmarks or performance levels defined in different ways, with no common definition of 'at risk' — a narrower finding that bears on this claim
• Definitions and measures of early childhood exclusion vary widely across studies, including soft-expulsion practices that only one study captured. — related
• Sample selection criteria moderate MLD effect sizes: stricter cutoffs, specificity, and age change group differences — a narrower finding that bears on this claim
• Only four screeners demonstrated acceptable diagnostic accuracy for distinguishing children with or at-risk of mathematical learning difficulties — related
• Included studies show considerable variation in the cut-off criteria used to identify students with co-occurring mathematics and reading difficulties — a narrower finding that bears on this claim