How Variable are Interstate Prevalence Rates of Learning Disabilities and other Special Education Categories? A Longitudinal Comparison

Abstract

This study compared interstate variability of prevalence rates for special education categories from 1984 to 1985 through 2001 to 2002, using the coefficient of variation (CV), which is designed to compare variances when the means of the groups compared are radically different. The category of learning disabilities, presumed by many to be the most variable, was consistently the least variable. Furthermore, as a group, high incidence categories were less variable than low incidence categories. The results strengthen the conclusion of Hallahan, Keller, & Ball (1986) that using state-to-state variability of disability prevalence rates as justification for criticizing learning disabilities identification practices is largely unfounded. Policy implications for methods of learning disabilities identification are discussed.

Get full access to this article

View all access options for this article.

References

Algozzine

Korinek

(1985). Where is special education for students with high prevalence handicaps going?. Exceptional Children, 51 (5), 388–394.

Batsche

Elliott

Graden

J. L.

Grimes

Kovaleski

J. F.

Prasse

(2005). Response to intervention: Policy considerations and implementation. Alexandria, VA: National Association of State Directors of Special Education.

Carrier

J. G.

(1986). Learning disability: Social class and the construction of inequality in American education. Westport, CT: Greenwood Press.

Coles

(1987). The learning mystique: A critical look at “learning disabilities.” New York: Pantheon.

Denton

C. A.

Vaughn

Fletcher

J. M.

(2003). Bringing research-based practice in reading intervention to scale. Learning Disabilities Research & Practice, 18, 201–211.

Donovan

Cross

C. T.

(Eds.). (2002). Minority students in special and gifted education. Washington, DC: National Academies Press.

Faber

D. S.

Korn

(1991). Applicability of the coefficient of variation method for analyzing synaptic plasticity. Biophysical Journal, 60, 1288–1294.

Finlan

(1994). Learning disabilities: The imaginary disease. Westport, CT: Gergin & Harvey.

Fletcher

J. M.

Lyon

G. R.

Barnes

Stuebing

K. K.

Francis

D. J.

Olson

R. K.

(2002). Classification of learning disabilities: An evidenced-based evaluation. In Bradley

Danielson

Hallahan

D. P.

(Eds.), Identification of learning disabilities: Research to practice (pp. 185–250). Mahwah, NJ: Lawrence Erlbaum.

10.

Friedman

(1972). Introduction to statistics. New York: Random House.

11.

Fuchs

Mock

Morgan

P. L.

Young

C. L.

(2003). Responsiveness-to-intervention: Definitions, evidence, and implications for the learning disabilities construct. Learning Disabilities Research & Practice, 18, 157–171.

12.

Gerber

M. M.

(2005). Teachers are still the test: Limitations of response to instruction strategies for identifying children with learning disabilities. Journal of Learning Disabilities, 38, 516–524.

13.

Hallahan

D. P.

Keller

C. E.

Ball

D. W.

(1986). A comparison of prevalence rate variability from state to state for each of the categories of special education. Remedial and Special Education, 7 (2), 8–14.

14.

Hamilton

B. E.

Martin

J. A.

Sutton

P. D.

(2004, November 23). Births: Preliminary data for 2003. National Vital Statistics Reports, 53 (9), 1–20.

15.

Hoyert

D. L.

Kung

Smith

B. L.

(2005, February 28). Deaths: Preliminary data for 2003. National Vital Statistics Reports, 53 (15), 1–48.

16.

Investopedia.Com . (1999–2006). Coefficient of variation—CV. Retrieved March 8, 2006, from http://www.investopedia.com/terms/c/coefficientofvariation.asp.

17.

Kavale

K. A.

(2005). Identifying specific learning disability: Is responsiveness to intervention the answer?. Journal of Learning Disabilities, 38, 553–562.

18.

Kavale

K. A.

Forness

S. R.

(1998). The politics of learning disabilities. Learning Disability Quarterly, 21, 245–273.

19.

Lang

T. A.

Secic

(1997). How to report statistics in medicine: Annotated guidelines for authors, editors, and reviewers. Philadelphia, PA: American College of Physicians.

20.

Lyon

G. R.

Fletcher

J. M.

Shaywitz

S. E.

Shaywitz

B. A.

Torgesen

J. K.

Wood

F. B.

(2001). Rethinking learning disabilities. In Finn

C. E.

Rotherham

A. J.

Hokanson

C. R.

(Eds.), Rethinking special education for a new century (pp. 259–287). Washington DC: Thomas B. Fordham Foundation and the Progressive Policy Institute.

21.

MacMillan

D. L.

Siperstein

G. N.

(2002). Learning disabilities as operationally defined by schools. In Bradley

Danielson

Hallahan

D. P.

(Eds.), Identification of learning disabilities: Research to practice (pp. 287–333). Mahwah, NJ: Lawrence Erlbaum.

22.

Mastropieri

M. A.

Scruggs

T. E.

(2005). Feasibility and consequences of response to intervention: Examination of the issues and scientific evidence as a model for the identification of individuals with learning disabilities. Journal of Learning Disabilities, 38, 525–531.

23.

McLennan

Lewer

(Reviewed 2005, February). Wool production: Coefficient of variation of fibre diameter (CVFD). Queensland Department of Primary Industries and Fisheries. Retrieved March 7, 2006, from http://www2.dpi.qld.gov.au/sheep/10003.html.

24.

National Center for Chronic Disease Prevention and Health Promotion. (2005). Behavioral Risk Factor Surveillance System (BRFSS) Prevalence Data. Available from National Center for Chronic Disease Prevention and Health Promotion Web site: http://apps.nccd.cdc.gov/brfss/index.asp.

25.

National Center for Health Statistics. (October 2001). 1999 Natality Data Set [CD-ROM Series 21, No. 12, SETS 2.0 Rev. 805]. Hyattsville, MD: U.S. Department of Health and Human Services.

26.

Patel

J. K.

Patel

N. M.

Shiyani

R. L.

(2001). Coefficient of variation in field experiments and yardstick thereof—An empirical study. Current Science, 81, 1163–1164.

27.

Portney

L. G.

Watkins

M. P.

(1993). Foundations of clinical research: Application to practice. Norwalk, CT: Appleton & Lange.

28.

Reed

G. F.

Lynn

Meade

B. D.

(2002). Use of coefficient of variation in assessing variability of quantitative assays. Clinical and Diagnostic Laboratory Immunology, 9, 1235–1239.

29.

Reschly

D. J.

(2002). Change dynamics in special education assessment: Historical and contemporary patterns. Peabody Journal of Education, 77, 117–136.

30.

Reschly

D. J.

Hosp

J. L.

(2004). State SLD identification policies and practices. Learning Disability Quarterly, 27 (4), 197–213.

31.

Siegel

(1989). IQ is irrelevant to the definition of learning disabilities. Journal of Learning Disabilities, 22, 469–486.

32.

Siegel

(1992). An evaluation of the discrepancy definition of dyslexia. Journal of Learning Disabilities, 25, 618–629.

33.

Sleeter

C. E.

(1986). Learning disabilities: The social construction of a special education category. Exceptional Children, 53, 46–54.

34.

Sleeter

C. E.

(1998). Yes, learning disabilities is political: What isn't?. Learning Disability Quarterly, 21, 289–296.

35.

Sokal

R. R.

Rohlf

F. J.

(1995). Biometry (3rd ed.). New York: W. H. Freeman.

36.

Stanovich

K. E.

(1991). Discrepancy definitions of reading disability: Has intelligence led us astray?. Reading Research Quarterly, 26 (1), 1–29.

37.

Stanovich

K. E.

(1993). The construct validity of discrepancy definitions of reading disability. In Lyon

G. R.

Gray

D. B.

Kavanagh

J. F.

Krasnegor

N. A.

(Eds.), Better understanding learning disabilities: New views from research and their implications for education and public policies (pp. 273–307). Baltimore, MD: Paul H. Brooks.

38.

U.S. Department of Education. (1986). Eighth annual report to Congress on implementation of the Education of the Handicapped Act. Washington, DC: Author.

39.

U.S. Department of Education. (1994). Sixteenth annual report to Congress on implementation of the Individuals With Disabilities Education Act. Washington, DC: Author.

40.

U.S. Department of Education. (1995). Seventeenth annual report to Congress on implementation of the Individuals With Disabilities Education Act. Washington, DC: Author.

41.

U.S. Department of Education. (2003). Twenty-fifth annual report to Congress on implementation of the Individuals With Disabilities Education Act. Washington, DC: Author.

42.

U.S. Department of Education Office of Special Education and Rehabilitative Services. (2002). A new era: Revitalizing special education for children and their families. Washington, DC: Author.

43.

Vaughn

Fuchs

L. S.

(2003). Refining learning disabilities as inadequate response to instruction: The promise and potential problems. Learning Disabilities Research & Practice, 18, 137–146.

44.

Vellutino

F. R.

Scanlon

D. M.

Sipay

E. R.

Small

S. G.

Pratt

Chen

(1996). Cognitive profiles of difficult-to-remediate and readily remediated poor readers: Early intervention as a vehicle for distinguishing between cognitive and experiential deficits as basic causes of specific reading disability. Journal of Educational Psychology, 88, 601–638.

45.

Weber

E. U.

Shafir

Blais

A-R.

(2004). Predicting risk sensitivity in humans and lower animals: Risk as variance or coefficient of variation. Psychological Review, 111 (2), 430–445.

46.

Ysseldyke

J. E.

Algozzine

(1984). Introduction to special education. Boston: Houghton Mifflin.