Socioeconomic status (SES) affects cultural perspective and speech and language development and can be found in testing materials and the evaluator’s interpretation of assessment performance.
In testing materials, it is evident in the items incorporated into the design of most norm-referenced tests. For example, vocabulary size has been correlated to SES background in numerous studies and has been found to be a diagnostically innaccurate method of identifying individuals with language disorders (Hart & Risley, 1995; Pruitt, Oetting & Hegarty, 2011; Roseberry-McKibbin, 2008). However, numerous commercial norm-referenced vocabulary tests still exist (ex. PPVT, EOWPVT, ROWPVT) although they have not been demonstrated to be diagnostically useful. Yet, many evaluators still rely on these tests to diagnose language disorders.
Norm-referenced tests are also typically biased against children from lower SES backgrounds because the normative/standardization sample is often largely made up of participants from middle SES. Due to this, the norms often indicate children of low SES to be delayed in development in comparison. Finally, the evaluator him or herself can be the source of bias if he/she expects children from other SES backgrounds to behave and develop in the way they would expect children from their own SES background to behave and develop. For example, children from low SES backgrounds may have less exposure to books or parents may have less time to provide linguistic stimulation. Research has demonstrated that the development of children living in poverty is affected from the womb to adulthood. This includes higher levels of detrimental chemicals released into the brain due to high-stress situations and decreased opportunities for quality health care (Roseberry-McKibbin, 2008). As a result, these children will perform differently in an evaluation and demonstrate different skills than children from middle or upper SES backgrounds.
Children should always be compared to peers from a similar environment to determine if they differ significantly enough to warrant a label of language impairment and a label of disability. Consider the case of the Wechsler Intelligence Scale for Children, Fourth Edition- Spanish (WISC-IV Spanish). After the test designers conducted a normative study to establish typical performance, they analyzed the data they had collected. The test designers noted significant differences in the performance of subgroups of the normative sample: Group A and Group B. Group A was composed of children who had less than 5 years of schooling in the U.S. and whose parents had only an 8th grade education. Children in Group B had more than 5 years of schooling in the U.S. and their parents were college graduates. The rankings show that a child in group A who scores 100 (in the 50th percentile for the normative sample in general) is actually at the 90th percentile when compared to other children in group A. Alternatively, a child from group B who scores 100, is actually at the 37th percentile when compared to other children from group B. In this situation, a child from group B that scored an 85 would, in fact, be about 1.5 standard deviations away from the mean (the amount necessary in some places to qualify for speech services and an IEP) when compared to other children from group B. Yet he would fall within the typically developing range when compared with the general normative sample. Conversely, a child from group A who scored a 68 would be considered cognitively impaired but when compared to other children from group B he would be typically developing. Consequently, children in Group A may be mislabeled as being cognitively impaired when they are not while children from Group B with actual cognitive impairment may not be diagnosed and not receive the services that could help support their development.
Hart, B. & Risley, T.R. (1995). Meaningful Differences in the Experiences of Young American Children. Baltimore, MD: Paul H. Brookes Publishing.
Pruitt, S., Oetting, J. & Hegarty, M. (2011). Passive Participle Marking by African American English-Speaking children reared in Poverty. Journal of Speech, Language, and Hearing Research, 54, 598-607.
Roseberry-McKibbin, C. (2008). Increasing the language and academic skills of children in poverty: Practical strategies for professionals. San Diego: Plural Publishing.