Abstract
Test Description
The Speed DIAL-4 was developed from the Developmental Indicators for the Assessment of Learning, Fourth Edition (DIAL-4), a screening designed to identify children between the ages of 2 years, 6 months through 5 years, 11 months “who are in need of intervention or diagnostic assessment in the following areas: motor, concepts, language, self-help, and social-emotional skills” (Mardell & Goldenberg, 2011, p. 1). Published by Pearson, the Speed DIAL-4 is a shortened version of the DIAL-4 and provides information about performance in three areas: motor, concepts, and language. The original version of the Speed DIAL was released in English and Spanish in 1998 and was based on the DIAL-3. The Speed DIAL-4 was published in 2011.
Throughout the development of the assessment, early childhood experts were consulted regarding the creation and inclusion of items on the Speed DIAL-4 to determine their practicality and ability to represent performance in the domains of child development and future academic success. Other professionals with expertise in both English and Spanish were consulted regarding aspects of the Spanish language items. A survey was sent to 800 early childhood professionals for their input regarding the revisions to the DIAL-3. The responses provided by 85 of these professionals, the input provided by other early childhood professionals, the comprehensive literature review in the areas of early childhood development and school readiness skills, and the recommendations provided by various state and federal agencies were used to create the current versions of the DIAL-4 and Speed DIAL-4.
The administration of the Speed DIAL-4 requires the use of the Speed DIAL-4 Operator’s Handbook and is designed to be completed in approximately 20 minutes on an individual basis. The operator should be familiar with the standardized administration of the Speed DIAL-4 and be able to work with children of diverse linguistic and cultural backgrounds. While the instructions differ for each item, they consist of a few simple and direct sentences, making administration concise and easy to follow.
Specific Description and Scoring
Motor skills are measured using Item 1 (stand, hop, and skip) and Item 10 (copying); Concepts are measured using Items 2-5 (body parts, rapid object naming, colors, and meaningful counting); and Language is measured using Items 6-9 (articulation, actions, letters and sounds, and problem solving). Responses on the Speed DIAL-4 are first evaluated using the scoring guide provided in the administration manual and item scores are summed to determine the Total Item Raw Score. If a child refuses to participate, it is indicated on the record form and administration is stopped. If a child does not attempt a task, the child receives a score of 0 and “NA” (no attempt) is marked for that task. This score is then converted to a Weighted Score “to ensure equal weighting of each item to the total score from each performance area” (Mardell & Goldenberg, 2011, p. 39). After scores for each of the Speed DIAL-4 items are calculated, weighted scores for all items are added up to determine the Total Weighted Score .
A cutoff level must be chosen to determine if a child’s performance indicates potential developmental delay, a decision that is usually made prior to administration and is uniform among all examiners from a particular school or organization. The overall decision of whether the child has a “Potential Delay” or is “OK,” according to the manual, is determined solely based on the Total Weighted Score. According to standardized norms, 16% of the normative sample would be classified as having a “Potential Delay”. Additionally, the cutoffs at 10%, 7%, 5%, and 2% represent various levels of performances that are at least 1 standard deviation below the mean and are used when making an overall decision about whether or not the child has a “Potential Delay” or is “OK” in terms of their performance. The Total Weighted Score may also be used to find the child’s percentile rank compared to other children in the same 2-month age group (2 years, 6 months to 2 years, 7 months, etc.) using the provided norms tables. The child’s standard score (M = 100, SD = 15) may also be determined using the percentile rank and provided norm table.
Test Materials and Stimuli
The Speed DIAL-4 includes an operator’s handbook, manual, concepts blocks, record forms in English and Spanish, and four large dials. The concepts blocks are a set of 12 assorted colored blocks and the large dials include clearly drawn pictures and a rotating disc that reveals each picture one at a time. The operator’s handbook provides step-by-step, standardized instructions (in English and Spanish) for each of the screening probes and scoring keys for item responses. The operator’s handbook also includes information for each item about the age range for that item, materials needed, illustration of the item, exact wording for administering the item, task scoring guidelines, special instructions, and item scoring instructions.
The manual includes information regarding the theoretical and research basis behind the test, preparation and administration of the test, scoring and interpretation of the items, procedures and norms, as well as information on many other areas in regard to the Speed DIAL-4. The manual for the Speed DIAL-4 is the same manual for the DIAL-4. Record forms have areas in which to record scores as well as space to write comments.
Technical Adequacy
Standardization Sample
The aspect of the norming process from the DIAL-4 taken into consideration for the Speed DIAL-4 was the performance areas norm sample (N = 1,400). The sample consisted of English- and Spanish-speaking children between the ages 2 years, 6 months and 5 years, 11 months who lived in the United States or Puerto Rico, from which the majority of the Spanish forms were collected. The target for Spanish-speaking examinees was 13%, consistent with the percentage of children in the U.S. whose primary language is Spanish (U.S. Census Bureau, 2008). With English and Spanish samples being treated as two different groups from within the same population, joint item calibrations were conducted to link the English- and Spanish-version items, allowing the ability estimates to be on the same scale. The authors also included information on sex, race/ethnicity, geographic region, mother’s educational level (SES), children’s educational setting, and children with a clinical diagnosis and determined that the sample reflected or closely reflected the proportions in the U.S. population.
Reliability
Internal consistency and test–retest stability were used to evaluate the reliability of Speed DIAL-4 test scores. The split-half reliability method was used to correlate the scores on two halves of the test, by dividing the tasks into two groups with “equal difficulty, content coverage, and score variance” (Mardell & Goldenberg, 2011, p. 53). Fischer’s z transformations were used to determine the split-half reliability coefficients for the three performance areas of Motor, Concepts, Language, and on the overall Speed DIAL-4. The split-half reliability coefficients for the English version of the Speed DIAL across age groups ranged from .84 to .94, with standard errors of measurement (SEM) from 1.7 to 2.1. While most of the split-half reliability coefficients were .91 or higher, the 5:6-5:11 age group had the lowest split-half coefficient (.84). The Spanish version of the Speed DIAL-4 had split-half coefficients across age groups ranging from .93 to .96, with SEMs from 1.2 to 2.1. Overall, the high split-half reliability values suggest the scores were internally consistent.
Test–retest stability was measured by calculating the correlation coefficients of two test administrations separated by a short time interval among the same sample. The correlation coefficients were based on responses from 93 English-speaking children and 81 Spanish-speaking children, who were stratified on various demographic variables (i.e., sex, race, SES, and region) but were not exactly representative of the U.S. population. These correlations were calculated across two age ranges (i.e., 2:6-3:11 and 4:0-5:11). The adjusted correlation coefficient for the English version of the Speed DIAL-4 was .78 for the younger group and .84 for the older group. The adjusted correlation for the Spanish version was .89 for both age groups. SEM values for the test–retest correlations were unsuitable for the statistic, so none were provided. These high correlation coefficients suggest stability across all age groups over time, although the specific amount of time between the two test administrations was not reported. However, the developmental capabilities of children in the lower end of the age ranges (e.g., 2:6-3:11) greatly differ from those in the upper end and should be taken into consideration.
Validity
The Speed DIAL-4 contains “10 core items selected from the Motor, Concepts, and Language performance areas” from the DIAL-4 (Mardell & Goldenberg, 2011, p. 2). Rationales substantiated by corresponding literature reviews support the incorporation of the tasks in the DIAL-4 as being representative not only of the desired constructs but also as being indicators of risk for academic failure, an important goal of the Speed DIAL-4.
A variety of analyses established construct validity. The high degree of correlation between the Speed DIAL-4 score and the DIAL-4 Total score (Z’ = .94 for the English versions; Z’ = .95 for the Spanish versions) suggests that the Speed DIAL-4 does a good job at measuring what the larger DIAL-4 is also intending to measure. Additionally, the Motor, Concepts, and Language performance areas of the DIAL-4 were highly correlated with the Speed DIAL-4 score (Z’ = .60, Z’ = .85, and Z’ = .87, respectively, for the English versions and Z’ = .63, Z’ = .87, and Z’ = .91, respectively, for the Spanish versions), illustrating that these performance areas contributed to the Speed DIAL-4 scores. Evidence of convergent validity (in this case, the Concepts and Language performance areas were moderately correlated with Z’ = .68) and discriminant validity (in this case, the Motor performance area was not highly correlated with the Concepts and Language areas, Z’ = .49 and Z’ = .44, respectively) further establish the construct validity of the screening.
Scores on the DIAL-4 and Speed DIAL-4 were compared to other existing assessments intended to measure similar constructs. The Speed DIAL-3 and the Speed DIAL-4 were highly correlated (adj r = .83), suggesting that even though the Speed DIAL-4 included revisions, it was still strongly related to the previous version that measured performance in the three areas. The DIAL-4 and Speed DIAL-4 were compared to other instruments such as the Early Screening Profiles (ESP), the Battelle Developmental Inventory, Second Edition (BDI-2), and the Differential Ability Scales, Second Edition (DAS-II). The ESP does not list a composite score for comparison with the Speed DIAL-4, but the corrected correlations were low to moderate between the Speed DIAL-4 and the BDI-2 and the DAS-II (r = .55 and r = .67, respectively). Higher degrees of correlation between the Speed DIAL-4 and the BDI-2 and the DAS-II would have been ideal, but this is unlikely given that the aforementioned assessments measure more than the three constructs included in the Speed DIAL-4.
Commentary and Recommendations
The Speed DIAL-4 is a screening instrument designed to identify children in early childhood who need an intervention or diagnostic assessment in the Language, Motor, and Concepts skill areas. The screening fits the theoretical and research basis described in the manual, and the standardization sample used is representative of both English- and Spanish-speaking children in the U.S. population. By having the screening in both English and Spanish, the screening can be used with a larger portion of the population that may be in need of available services. The sample included five racial/ethnic categories and was representative of the four regions (Northeast, Midwest, South, and West) of the United States.
Despite strengths of the Speed DIAL-4, there are some weaknesses in design and implementation. For instance, there was only an 11% return rate of the 800 surveys sent to the early childhood experts, which is unlikely to provide sufficient and varied feedback to obtain a holistic perspective on the various factors related to early childhood development. Additionally, although high correlations were reported for test–retest reliability, the authors did not disclose the amount of time that passed between the testing periods. It may be possible that a short amount of time between test administrations could have allowed practice effects to play a role in the high test–retest correlations. Another weakness of the Speed DIAL-4 involves knowledge of the Spanish alphabet on the Spanish version. The lower rate of parent-child book reading in Spanish-speaking homes compared to English-speaking counterparts decreases the likelihood that Spanish-speaking children would be formally instructed on the Spanish alphabet (Adams, 1990). Full credit is given for the Spanish-speaking version if the child responds in English or Spanish, but expecting a child to recite the Spanish alphabet is unlikely. Lastly, the distracter block used in the identification of colors in Item 4 often results in a point deduction since children can confuse it with the actual brown block in the set. No rationale is included as to why the distractor block is needed, so eliminating the distracter block could increase the reliability for this item. Overall, the Speed DIAL-4 is an easy-to-use screening measure that does not take a lengthy amount of time and can be administered in both English and Spanish.
Footnotes
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.