The Social Language Development Test is a norm-referenced measure of social language skills for ages 6 to 17, published by PRO-ED in two age-based forms.
Dr. Russell T. WarneChief Scientist
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The Social Language Development Test is a norm-referenced, individually administered assessment of how well a child or teenager uses language in social situations. PRO-ED publishes it in two age-based forms: an elementary form for children ages 6-0 through 11-11 and an adolescent form for students ages 12-0 through 17-11. Each form takes about 45 minutes and is scored against national norms. This article covers what the test measures, how the two forms are built, what the scores mean, and where a social language measure sits relative to a cognitive ability test.
What the test measures
The Social Language Development Test targets "pragmatic language," the part of communication that governs how people use language with each other rather than how they build sentences. A child can have intact vocabulary and grammar and still struggle to read a friend's intent, take another person's perspective, or repair a disagreement without damaging the friendship.
According to PRO-ED, the elementary form assesses "language-based skills of social interpretation and interaction with friends," specifically the language needed to infer and express what another person is thinking or feeling, to generate multiple interpretations of an ambiguous situation, to take mutual perspectives, and to negotiate with and support peers. The adolescent form is described in similar terms, measuring a student's ability to make inferences and to interpret and respond to social interaction.
Both forms were written by Linda Bowers, Rosemary Huisingh, and Carolyn M. LoGiudice. The test originated with LinguiSystems, whose assessment catalog PRO-ED now carries; the old linguisystems.com domain no longer resolves.
One point matters for anyone comparing options. The current products are the Normative Update editions, abbreviated SLDT-E: NU and SLDT-A: NU, both carrying a 2017 copyright. PRO-ED's catalog still lists forms for the previous adolescent edition, which is a common source of confusion when a school's test cupboard holds an older kit.
The elementary form, ages 6 to 11
The elementary edition covers children from 6 years 0 months through 11 years 11 months. PRO-ED lists testing time at 45 minutes, individual administration, and test level B.
The publisher describes four subtests that ask students to make inferences, interpret photographed scenes, and explain how they would resolve problems with peers. An outcome-measure summary compiled by the Moving Ahead research centre at the University of New South Wales names the four as follows.
• Making inferences: The child looks at a photograph of a peer situation and says what the person in the picture is likely thinking, drawing on facial expression, body language, and context.
• Interpersonal negotiation: The child is given a conflict between friends and has to state the problem from a shared perspective and propose a solution that keeps the friendship intact.
• Multiple interpretations: The child offers two different but plausible readings of the same ambiguous photograph, which taps flexible thinking rather than a single correct answer.
• Supporting peers: The child takes the perspective of a character and says something supportive to a friend, including cases where a kind response differs from a blunt one.
PRO-ED reports average coefficient alpha between .77 and .92 across the elementary subtests and .94 for the composite.
The adolescent form, ages 12 to 17
The adolescent edition covers students from 12 years 0 months through 17 years 11 months, also at 45 minutes and individual administration. PRO-ED names its five subtests directly: Making Inferences, Interpreting Social Language, Problem Solving, Social Interpretation, and Interpreting Ironic Statements. The audio files used for the irony subtest are available online, which replaced the CD that shipped with earlier kits.
Irony is the task that most clearly separates this form from the elementary one. Detecting that a speaker means the opposite of the literal words requires holding tone and speaker intent together, and it develops later than basic inference.
PRO-ED reports average coefficient alpha between .76 and .86 for the adolescent subtests and .95 for the composite. The publisher also states that the adolescent normative sample includes 868 students, stratified by age relative to geographic region, gender, race, and ethnicity, with norms reflecting the 2016 U.S. Census. The elementary norms were updated against the 2015 U.S. Census.
How the scores work
Both Normative Update editions moved to a familiar psychometric metric. Subtests yield "scaled scores" with a mean of 10 and a "standard deviation" of 3, meaning a measure of how spread out scores are. The subtests combine into a composite called the Social Language Development Index, reported on a mean-100, standard-deviation-15 scale. That is the same scale used for IQ scores, so a Social Language Development Index of 85 sits one standard deviation below the normative average in the same way an IQ of 85 does.
The publisher also reports diagnostic accuracy statistics, which are worth reading carefully. PRO-ED states that an index cutoff score of 90 produced a sensitivity of .82, a specificity of .86, and an area under the curve of .91 for the elementary form, and a sensitivity of .71, a specificity of .96, and an area under the curve of .90 for the adolescent form. "Sensitivity" is the share of students with the condition that the test correctly flags, and "specificity" is the share of students without it that the test correctly clears. The adolescent figures describe a test that rarely mislabels a typically developing teenager but misses roughly three in ten of the students it is meant to identify.
Every score of this type carries measurement error, so a single index value should be read as a band rather than a point. Practitioners use confidence intervals for that reason.
What the test does well, and where it falls short
The test earns its place because it asks students to produce social language rather than recognize it in a multiple-choice format. Open-ended responses scored against exemplars capture something a checklist cannot.
The limitations deserve equal attention. An independent master's thesis at Miami University examined the accuracy of the earlier editions against a parent-report measure and found sensitivity of just 33% for both forms, with specificity of 100% for the elementary version and 75% for the adolescent version. That study rested on a very small sample, 6 students with social language impairment and 17 typically developing peers, and it predates the Normative Update. It still illustrates a gap between publisher-reported accuracy and performance in an independent clinic sample.
The broader concern applies to every deskbound pragmatic language measure. The American Speech-Language-Hearing Association notes a lack of ecological validity in standardized assessments given the dynamic nature of social communication, and recommends combining formal and informal approaches with naturalistic observation and data from multiple sources. Research by Volden and Phillips supports that caution: among children with autism who had age-appropriate structural language, a parent-report checklist identified 13 of 16 as pragmatically impaired while a direct pragmatic language test identified only 9.
Structural language also has to be ruled in or out first. Work by Reindal and colleagues on 177 children evaluated for autism found that structural language deficits were common and were associated with reduced pragmatic competence in both the autistic and non-autistic groups. A student who cannot follow the examiner's scenario may score low for reasons that have nothing to do with social reasoning, which is why clinicians typically pair a social language measure with a core language battery and with a semantic or vocabulary measure such as the Test of Semantic Skills.
For readers weighing alternatives, the Test of Pragmatic Language covers overlapping ground with a wider age span and a different task design. The Social Language Development Test leans harder on peer-conflict scenarios and photographed social scenes, and its published validity work is anchored to autism spectrum samples, so the two instruments answer slightly different referral questions.
How a social language test relates to cognitive testing
A social language measure is not an intelligence test, and its index should never be read as an IQ estimate. The two share a score scale and little else. A student can post a well-above-average IQ and a below-average Social Language Development Index, and that pattern is part of why the relationship between IQ and autism resists simple summary. Cognitive tests sample reasoning, memory, and speed under standardized conditions; the Social Language Development Test samples one narrow domain of communicative competence.
When a full picture of reasoning ability is the goal, a general cognitive measure is the right tool. The Reasoning and Intelligence Online Test, developed by RIOT IQ with psychometrician Dr. Russell T. Warne, is built for adults 18 and older and runs 15 subtests across six cognitive indices covering verbal reasoning, fluid reasoning, spatial ability, working memory, processing speed, and reaction time. It takes about 52 minutes and reports scores on the same mean-100, standard-deviation-15 scale described above. It does not replace an individually administered diagnostic evaluation, and it is not a social communication measure. Adults curious about where their reasoning skills stand against a normative sample can take the RIOT IQ test.
Frequently asked questions
Who can administer the Social Language Development Test?
PRO-ED lists both Normative Update editions at test level B, and the tasks call for a professional familiar with language disorders, typically a speech-language pathologist or psychologist. Scoring open-ended responses against the exemplar book requires clinical judgment, so training matters more here than on a multiple-choice measure.
How long does the test take?
PRO-ED lists 45 minutes for both the elementary and the adolescent form, administered individually. Scoring the open-ended responses adds time beyond the administration itself.
What is the Social Language Development Index?
It is the composite score that summarizes performance across the subtests, reported on a scale with a mean of 100 and a standard deviation of 15. Individual subtests are reported as scaled scores with a mean of 10 and a standard deviation of 3.
Is the Social Language Development Test a diagnostic test for autism?
No. The publisher reports that performance differentiates typically developing students from those previously diagnosed with autism spectrum disorder, and reports sensitivity and specificity at an index cutoff of 90. An autism diagnosis rests on a multidisciplinary evaluation, and this test contributes one strand of evidence about social language.
Which edition should a school be using?
The current products are the Normative Update editions, SLDT-E: NU and SLDT-A: NU, both copyright 2017. Older kits use earlier norms and a different score metric, so results from the two are not interchangeable.
Does a low score mean a child has low intelligence?
No. The test samples social language and nothing else. Scores describe performance on a specific set of tasks, not a person's overall ability, and a student can score poorly here while performing well on measures of reasoning.
References
1. PRO-ED. (2017). SLDT-E: NU: Social Language Development Test–Elementary: Normative Update, Complete Kit. proedinc.com
2. PRO-ED. (2017). SLDT-A: NU: Social Language Development Test–Adolescent: Normative Update, Complete Kit. proedinc.com
3. Moving Ahead, University of New South Wales. (n.d.). Outcome measure: Social Language Development Test (SLDT) (Elementary and Adolescent versions). movingahead.psy.unsw.edu.au
4. American Speech-Language-Hearing Association. (n.d.). Social communication disorder [Practice portal]. asha.org
5. Zeberlein, J. C. (2014). Examination of the accuracy of the Social Language Development Test for identification of social language impairments [Master's thesis, Miami University]. OhioLINK Electronic Theses and Dissertations Center. rave.ohiolink.edu
6. Volden, J., & Phillips, L. (2010). Measuring pragmatic language in speakers with autism spectrum disorders: Comparing the Children's Communication Checklist-2 and the Test of Pragmatic Language. American Journal of Speech-Language Pathology, 19(3), 204-212. pubmed.ncbi.nlm.nih.gov
7. Reindal, L., Nærland, T., Weidle, B., Lydersen, S., Andreassen, O. A., & Sund, A. M. (2023). Structural and pragmatic language impairments in children evaluated for autism spectrum disorder (ASD). Journal of Autism and Developmental Disorders, 53(2), 701-719. doi.org
Hero photo: Four university students working through problem sets together around a shared table. Photo by Tulane Public Relations, via Wikimedia Commons, CC BY 2.0 (cropped).
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