Denver Developmental Screening Test

The Denver Developmental Screening Test (DDST), commonly known as the Denver Scale, is a developmental measure, and is a test for screening cognitive and behavioural problems] in [[preschool children. It was developed by William K. Frankenburg and first introduced by him and Josiah.B. Dobbs in 1967. The test is currently marketed by Denver Developmental Materials, Inc., in Denver, Colorado, hence the name.

The scale reflects what percentage of a certain age group is able to perform a certain task. In a test to be administered by a pediatrician or other health or social service professional, a subject's performance against the regular age distribution is noted. Tasks are grouped into four categories (social contact, fine motor skill, language, and gross motor skill) and include items such as smiles spontaneously (performed by 90% of three-month-olds), knocks two building blocks against each other (90% of 13-month-olds), speaks three words other than "mom" and "dad" (90% of 21-month-olds), or hops on one leg (90% of 5-year-olds).

According to a study commissioned by the Public Health Agency of Canada, the DDST is the most widely used test for screening developmental problems in children. While this study acknowledges the test's utility for detecting severe developmental problems, the test has been criticized to be unreliable in predicting less severe or specific problems. The same criticism has been upheld for the currently marketed revised version of the Denver Scale, the DENVER II. Frankenburg has replied to such criticism by pointing out that the Denver Scale is not a tool of final diagnosis, but a quick method to process large numbers of children in order to identify those that should be further evaluated.

This revised definition of the Denver's function remains commensurate with what screening tests are designed to do: sort those who probably have problems from those who probably don't. Thus standards for screening test construction still apply to the Denver. Although the instrument has proven reliability, it was not constructed on a large, current, nationally representative sample. It has not been studied for validity (given alongside diagnostic measures to view their relationship or researched for the kinds of problems it may or may not detect). As a consequence, the measure was not studied by its authors for the most critical attribute of any screen, its accuracy. Studies by other researchers showed it to detect only about 50% of children with disabilities, although its specificity in identifying normally developing children is high (when questionables are grouped with normal scores) and the converse when questionable scores are grouped with abnormal results. Since 1991, researchers have appealed to the author to recall and improve the measure but to no avail. Currently the measure is excluded from lists of recommended tools in several states (e.g., Minnesota Department of Education. For a list of accurate alternatives see The website of the American Academy of Pediatrics' Section on Developmental and Behavioral Pediatrics

DENVER II
The DENVER II (1992) is a revision and update of the Denver Developmental Screening Test, DDST (1967). Both were designed for use by the clinician, teacher, or other early childhood professional to monitor the development of infants and preschool-aged children. Doing so, enables the clinician to identify children whose development deviates significantly from that of other children warranting further investigation to determine if there exists a problem requiring treatment. The tests cover four general functions: personal social (such as smiling), fine motor adaptive (such as grasping and drawing), language (such as combining words), and gross motor (such as walking). Ages covered by the tests range from birth to six years. Since its publication the test has enjoyed widespread popularity as reflected by its use in many of this nation’s medical schools.

The DENVER II, published in 1992, was standardized on 2,096 children. Its interpretation was slightly modified from the DDST giving greater emphasis to a comparison of the child’s performance on each item with the new norms, much as clinicians have compared children’s growth on individual parameters as height, weight and head circumference to ascertain a child’s health status.

There are five unique features of the test that generally differentiates it from most other developmental screening tests:
 * 1) Its validity rests upon its meticulous and careful standardization reflecting the US 1980 census population. Most other developmental screening tests base their validity on measures of sensitivity and specificity. Most such studies suffer from one or more of the following: small sample size, verification bias, inappropriate/non- equivalent test bias, procedural bias, spectrum bias and incomplete reporting of results.
 * 2) Since the test depicts in graphic form the ages at which 25%, 50%, 75% and 90% of children performed each item, it enables the examiner to visualize at any age from birth to six years how a given child’s development compares with that of other children.
 * 3) The test has separate norms for subgroups of the population based on sex, ethnicity and maternal education when the subgroups differed by a clinically significant amount from the total group or composite norms.
 * 4) The test is primarily based upon an examiner’s actual observation rather than parental report.
 * 5) It is ideal for visualizing on one page the developmental progress of children whether or not their development is being monitored for well child care or because the child’s development is of special concern.

The above unique features of the test as well as its ease of administration and interpretation contribute to its widespread use in screening programs as public child health clinics, private practices, early education programs such as, nursery schools and day care centers. In fact, the DDST and the DENVER II test have been translated into numerous foreign languages, as well as re-standardized on over 1,000 children in each of 12 countries to obtain national norms, resulting in its use to screen millions of children throughout the world.

In 2006 the American Academy of Pediatrics Council on Children with Disabilities; Section on Developmental Behavioral Pediatrics published a list of screening tests for clinicians to consider when selecting a test to use in their practice. This list includes the DENVER II among its choices.

Most recently, the Denver II has fallen out of favor with early childhood organizations. The Minnesota Department of Public Health stated, "The Denver II (1989) is no longer a recommended developmental screening instrument for use in Minnesota public programs . . . The Denver II failed to meet review criteria. Review criteria is available online at http://www.health.state.mn.us/divs/fh/mch/devscrn/criteria.html. (accessed September 5, 2012 at http://www.health.state.mn.us/divs/fh/mch/devscrn/faq.html)

In addition, a leading provider of early childhood research based curriculum, Parents as Teachers, has told its affiliates that the Denver II is no longer a valid instrument for use in its affiliate programs.