A development quotient (DQ), most frequently used with infants or preschool children, is a numerical indicator of a child’s growth to maturity across a range of psychosocial competencies.
Typically, these include areas such as personal social development, attention span, expressive and receptive language, visuoperceptual skills, fine and gross motor skills, and initiative and independence, together with aspects of cognitive development, problem solving, and memory. A DQ should not be considered as a constant, but as a simplified index, reflecting changes in experience, patterns of interaction and learning over time, and summarizing the more detailed domain specific information from which it is derived. Unlike the intelligence quotient (IQ), the DQ is a ratio statistic reflecting a child’s overall development in relation to criteria logged in authentic social contexts. In contrast, the IQ is a deviation score based on statistical comparison of an individual’s performance on contrived tasks under highly controlled test conditions with normative data for a given age group.
In clinical and educational work, it may be desirable to construct an accurate, fine-grained profile of a child’s behavioral, communication, and intellectual development in order to inform an overall assessment of a child’s learning needs, to make a diagnosis, plan an intervention program, or identify resources required. Using direct observation, play-based assessment or problem-solving tasks, a detailed developmental profile may be constructed using criteria and age reference points drawn from the research literature.
There is an extensive body of work—more detailed in early infancy—documenting the age at which most children achieve milestones in development, such as following an adult’s line of gaze, crawling, reaching and grasping objects, and manipulating tools to perform tasks such as cutting or threading, as well as the appearance of speech sounds and word combinations in spoken language, moving on to more complex cognitive functions involving recall or reasoning. Age equivalent scores for each domain may be converted to ratios or quotients, for example, to derive a social or language DQ. The simplest procedure to calculate an overall general DQ is to divide the subject’s summated developmental age (DA) across domains by the chronological age (CA) and multiply by 100 (DQ = DA/CA × 100).
There are special situations where a developmental profile and DQ are very useful. For example, some children diagnosed with autistic spectrum disorder (ASD) or related communication and learning difficulties present uneven profiles, idiosyncratic response patterns to social and other stimuli, or noncompliance to formal testing. In fact, diagnosis of ASD is made from a consideration of such behavioral evidence. Materials such as the Psycho-Educational Profile–Revised (PEP-R) (Schopler et al., 1990) provide a flexible, non–time constrained framework for an examiner to observe, evaluate, and record responses in order to depict a child’s relative strengths in areas relevant to ASD, to plan intervention and monitor progress over time. A DQ derived from this or other informal assessment frameworks allows children’s individual developmental trajectories to be plotted over time in order to probe the impact of intervention strategies and avoids some of the pitfalls of standardized intelligence testing for atypical groups. (See Webster et al., 2003, for an illustration of this research methodology.)
- Allyn & (n.d.). Exploring child development. Retrieved from http://www.abacon.com/fabes/pages/timeline.html
- Schopler, E., Reichler, R. J., Bashford, A., Lansing, M. D., & Marcus, L. M. (1990). Psycho-Educational Profile– Revised (PEP-R). Austin, TX: Pro-Ed.
- Webster, A, Feiler, A., & Webster, V. (2003). Early intensive family intervention and evidence of effectiveness: Lessons from the South West Autism Early Child Development and Care, 173(4; Special Autism Issue), pp. 383–398.